Các số đó là:
102;120;210;201;300;111.
Vậy có 6 số.
1) my father (not smoke)........for 5 years
2) my leacher wasn't at home when i (arrive)......He(just go)......out
3)how long Bob and mary (be).....married?
4)you(receive).......any letter from your parents yet?
5)my brother(join)....the army when he (be) young
6)you(remember)..... my name or you (forget)......it someday
7)tom(study).....chemistry for three years and then he gave it up
8)miss lee often(write)..... when she was on holiday
9)he(leave).....home two weeks ago and we (not hear)......from him since then
10)you(speak)....to Mrs Baker yesterday?
no,i(not see)...her for a long time
i(not can)...remember when i last(see)....her
11)when the teacher came in, the pupils(play)...games