Some basic Grammar help needed

Hi, I've got some problems with Grammar, that I would like if people could help me out a little. I have listed my English translation below each, but I don't think I am fully correct with any of them...
Please, don't feel obliged to help. There is quite a bit to check up on, so if you want to only do a sentence or two, or none at all, or all of them!
Here it goes.

ともだちとたのしくあそびます。
(My) friend is playing enjoyably.

これは高い本です。
This is an expensive book.

大きいのはいくらですか。
How much is that big thing?

このスカートはきれいではありません。
This skirt is not pretty.

あの人はげんきではなかった。
That person was not healthy/That person was not fine.

あの人は元気でやさしいです。
That person was health and plain. (What the heck? I think it is and, because of the で particle in the middle)

あの人は漢字を上手に書きます。
That person is good at writing chinese characters.

つくえの上に本があります。
These is a book on the desk's top (desktop).
^ With this one is ある used to show the desk 'owns' the book? Is it similar to 'レストランをありますか。', 'is there a resteraunt' (but literally 'do have a restaurant?')

私は毎日本を読みます。
I read books every day. (The page I got it from was written as above, but I think it is supposed to be split - my confusion came from 日本 in the middle, and at first glance I thought it must be something about Japan, but then I thought 毎日could mean every day. Any help?)

Thanks! As said before, I know it is a lot to help me with, and grammar of all things () so I don't mind if you do only one or two sentences. Feel free to help if you want to, but DON'T FEEL OBLIGED TO DO SO>

^^ Thanks
Joe

ともだち と たのしく あそびます sounds like: Playing with my friend enjoyably.
ともだち は たのしく あそびます。is the sentence I would use.
You must have friend as subject, for that you have to use wa/ga.
The rest seems ok, however, you should wait until someone smarter than me appears, I may screw up, although probably I didn't.

ともだちとたのしくあそびます。
(My) friend is playing enjoyably.
As Derfel said, the particle と means that you are doing something with your friend.

これは高い本です。
This is an expensive book.

大きいのはいくらですか。
How much is that big thing?
in this case, の is a placeholder noun; "How much is the big one?"

このスカートはきれいではありません。
This skirt is not pretty.
fine, but ではありません is a bit too serious and emphatic for the subject; I would use "ja nai/ja arimasen"

あの人はげんきではなかった。
That person was not healthy/That person was not fine.
same as last time, this makes it seem like someone made a statement and you are strongly denying it.

あの人は元気でやさしいです。
That person was health and plain. (What the heck? I think it is and, because of the で particle in the middle)
genki as an adjective means "healthy/energetic," and yasashii means "nice/kind" when talking about a person (there is another yasashii with different kanji that means "easy"). The で is the te-form of だ, and it just links the two clauses (like "and").

あの人は漢字を上手に書きます。
That person is good at writing chinese characters.

つくえの上に本があります。
These is a book on the desk's top (desktop).
^ With this one is ある used to show the desk 'owns' the book? Is it similar to 'レストランをありますか。', 'is there a resteraunt' (but literally 'do have a restaurant?')
あります needs the に particle. In this case it is just saying where the book is.

私は毎日本を読みます。
I read books every day. (The page I got it from was written as above, but I think it is supposed to be split - my confusion came from 日本 in the middle, and at first glance I thought it must be something about Japan, but then I thought 毎日could mean every day. Any help?)
Your translation is correct, the sentence does not need to be split. Sometimes there are kanji compounds that can be confusing when they show up next to each other, but you'll get used to understanding from the context.

Thank you very much Derfel and Nice gaijin!

The list I am working from is from JLPTstudy.com.
It has different entries, some in casual and some in polite form. For example, there is
私は本を買った。as well as
私は本を買いました。
both under seperate entries, but meaning the same thing (I think...)

Any problems with the statements are due to JLPTstudy.com, but oh well. I'm too poor to buy any textbooks

Anyway, thanks loads for this! This is really helpful.

PS: I know this is JLPT 4 stuff, but to take JLPT 3 (I will take it in 2009) you need to know JLPT 4 things too...
Thanks again.
Joe

nice gaijin said:

私は毎日本を読みます。
I read books every day. (The page I got it from was written as above, but I think it is supposed to be split - my confusion came from 日本 in the middle, and at first glance I thought it must be something about Japan, but then I thought 毎日could mean every day. Any help?)
Your translation is correct, the sentence does not need to be split. Sometimes there are kanji compounds that can be confusing when they show up next to each other, but you'll get used to understanding from the context.

Click to expand...

Couldn't you have a に in there? 毎日に本を読みます。It sound a bit strange speaking but reading it looks like right. Specifying an amount or specific time I though you should use に.

Possibly. That sentence isn't based around the ni particle, so JLPTstudy.com may have been a bit off putting it down (although most of the sentences on there are supposedly from the test's specification.
That sentence is based on
'V+ます', (verb + masu, which would be why is it in it's polite form), but nothing about particles...

Thanks again.

ni is only used when there is a specific point in time mentioned, so it should not be used with words like mainichi, ashita, kinou, raishuu, etc

Cool, thanks. I have a great resource but she is confined to mainly english.

Other posters already covered them all quite well, so here's some additional explanation...

ともだちとたのしくあそびます。
(My) friend is playing enjoyably.

Click to expand...

Litereal translation would be:
(I*) play with my friend(s) joyfully.

*When there's no context, it is understood as a statement about the speaker, but it could be someone else if this sentence follows statement about others.

It is something close to "(I) enjoy playing with my friends."

つくえの上に本があります。
These is a book on the desk's top (desktop).
^ With this one is ある used to show the desk 'owns' the book? Is it similar to 'レストランをありますか。', 'is there a resteraunt' (but literally 'do have a restaurant?')

Click to expand...

ある means "to be/exist".
Literal translation is "On the desk is a book", which we usually say "there's a book on the desk" in English.

Thank you everyone for the help. It is greatly appreciated!

God, the Japanese language is full of animosity.