33.What did you do last night?

34.They have not learnt English for 4 years.

35.We should make blankets for chilren who are very ill.

36.The lakes are full of rubbish,so we should ask our friends to clean them this Sunday.

37.He's had a bad cold because he didn't wear enough warm clothes.

38.Although she likes walking,she never goes to school on foot.

39.Why don't you donate books to children?

40.I have taken part in doing voluntary work since 2015.

$\text{1.}$

$\text{Question 33.What did you do last night?}$

$\text{Question 34.They have learnt English for four years.}$

$\text{Question 35.We should make blankets for children who are very ill.}$

$\text{Question 36.The lakes are full of rubbish, so we should ask our friends to clean them this Sunday.}$

$\text{2.}$

$\text{Question 37.He’s had a bad cold because he didn’t wear enough warm clothes. (because+clause:bởi vì)}$

$\text{Question 38.Although she likes walking, she never goes to school on foot. (although+clause:mặc dù)}$

$\text{Question 39.Why don’t you donate books to children? (Why don't we/you + Verb (nguyên mẫu)...?)}$

$\text{Question 40.I have taken part in doing voluntary work since 2015.}$

$\text{(S+began/started+V_ing...=S+have/has+P.P+since/for+...)}$