Ответ в приложении на картинке
1 She said her mom works at the University.
2 Everyone thought the lecture would start at 10: 00.
3 We wanted to know when she came.
4 I didn't expect to see him again..
5 Parents were very happy that their daughter passed the entrance exams.
6 Everyone knew that she would go on a business trip, but did not know when she would return.
7 He didn't want to believe his friends didn't understand him
8 We didn't notice the children leaving the room.
9 He didn't say he didn't like going to the theatre.
10 She promised she'd send us a letter.
11 I couldn't understand why he didn't come.
Why do you keep avoiding me?
She burst out laughing suddenly
I cannot help thinking about it
He denies having broken the window
We enjoy reading this book
Excuse me interrupting
Have you finished explaining the rule?
I can not forgive him lying to me
When will you give up smoking?
She goes on dancing
They keep on talking
I do not mind you staying here
We'll have to postpone buying a new computer until next year
She stopped working at 5 o'clock
We decided to put off buying the house
The snow is coming (the употрябляем, так как снег единственный в своем роде)
I ate an apple (an употребляется, так как apple начинается с гласного звука)
I bought a book ( a употребляется так как book начинается с согласного звука)
Ну, думаю принцип вы поняли. Если слово в единственном числе начинается с гласного звука, то мы употребляем артикль an, если с согласного, то a).