4 Despite the dark sky, he took a lot of photographs.
5 I haven't seen him for 3 years.
6 The telephone was invented by Alexander Graham Bell in 1847.
7 Mary asked Tim if he liked her new dress at his birthday party the previous Sunday.
8 Rice is grown in tropical countries.
9 Huy is the tallest student in my class.
10 ALthough she is my old acquaintance, she can't understand me.
11 If you don't study hard, you won't pass the exam.
12 My father told me to wait there until he came back.
13 He has worked here since 2000.
14 The little girl who is wearing the red dress sings beautifully.
15 If she had enough money, she could buy that book.
16 It took us the whole day to look for these old pictures.
17 Jane has never visited Vietnam before.
18 My mother wishes she didn't live in such a small house.
19 Because it was raining, we decided to postpone our picnic.
20 If you don't take exercise regularly, you will get fit.
