must/may have + past participle

[hirashin]

Would someone check my sentences?
1 Mike isn't here yet. He must have missed his train.
2 That old man must have been a doctor. He knows a lot about diseases.
3 Tom may have been here while I was away.
4 Someone may have helped us. This work is almost finished.
5 I may have seen it before, but I'm not sure.
6 Mary must have been very young when she wrote this poem.
7 Someone[/Somebody] may have taken my textbook.
8 Tom may have been/come here yesterday morning.
9 Someone[/Somebody] must have used this pen.
10 John must have seen/watched this movie many times.
11 Mary must have practiced/practised (the) piano very hard.
12 That girl may have seen the traffic accident yesterday.
13 Someone[/Somebody] must have stolen my bike.
14 The/That woman may have been a famous pianist.
15 You may have been right/correct.

Thanks in advance.

Hirashin

 

[cloa513]

Almost all fine but technically 11 can only be practised as practise is a verb and practice is a noun. You can substitute "may" for "must" and "must" for "may" for just about any sentence but the meaning changes. Sometimes the change is large and has a somewhat odd meaning but still a valid sentence.

 

[Majestic]

In the US, practice is used as a verb as well as a noun.

 

[hirashin]

Thank you for the help, cloa513 and Majestic.
I'm relieved to know that my sentences are OK.
It's always challenging for me to make English problems for teaching.
Hirashin

 

[mdchachi]

I agree, all look good.

 

[hirashin]

Thanks for the help, mdchachi.