Помогите пожалуйста с заданием! Если несложно, то с разъясненьем почему именно

Помогите пожалуйста с заданием! Если несложно, то с изъясненьем почему конкретно такаю форму необходимо вставить.

Задание: Open the parentheses using the appropriate tense form.

1) Poirot watched for a minute or two an d _____________ back to the veranda, (to come)
2) A man may conceal his hate till the proper time _____ _________. (to come)
3) He____________ the bottle,_____________ his head aside, and t_______the solution into the nest, then stood back watching*, (to uncork, to turn, to pour)
4) Oh! Gerald, I wish I ______________more about you! (to know)
5) I saw you_____________of a doctors house, (to come out)
6) I ____________ it only once or twice in my lifetime, but it is not easily mistaken, (to see)
7) He has seen what I hear, what I could see perhaps if I _____________ his age. (to be)
8) I _____________one or two tea parties during this season, and they_______ ,_____quite a success, (to give, to be)
9) If you yourself at the house in half an hours time, I will make up a story to account for your presence, (to present)
10) It was not until after everyone ______________ that I discovered the safe rifled, (to go)
11) Countess_____________some family jewels with her from Russia. She is anxious to sell them, (to bring)
12) There was a man whose death__. three days before, (to take place)
13) She, who never ______________in her life, was a great actress at this moment, (to act)
14) I wish you ______________me play with that little boy. (to let)
15) What I was searching for, I hardly ______________. (to know)
16) Youve got more than your money_____________ worth in that basket of cherries, (to be)
17) What_____________the news? said Edward stretching himself flat on his back, (to be)
18) Baskets of fruit______________yesterday and (to be) on sale every Sunday, (to be sold)