Question Most suitable word?

[chamarawix]

支払おうと。。。。。かけたとき、財布がないことに気がついた。
１）し　２）する　３）した　４）して
I feel the answer is した and して. Please someone explain this to me.

 

[Toritoribe]

Have you already learned ～かける "to be about to do"? Check again what form of verbs is attached to かける in your textbook.

 

[chamarawix]

たべかけ。。読みかけ。。
So this would be しかけ？

 

[Toritoribe]

You got it!

 

[chamarawix]

Thanks.