练习一
present;since;doctor;
pollution;open;
D;A;B;A;C;B;B;AD;B;
was taught;married;
swim;came;have been;
have lived;was.
练习二
changes;seen;in fact;
marry;southern;had fun;
won"t until;have been married;
has kept;different from
AADBDABB
练习三possible;service;althgough;
attraction;present;have;
since;How many;When buy;
Have carried;been;hasn"t;sad;去掉
but;yet;next to;
has been opened;any longer;how to get;
It"s toread;It is came;
but came;have known;are fond of
练习四
CBACCB;not arrived;yet;How long;heard;Has ever been;Has changed;yet;
I have lived here since I was born.
It"s pleasant to play Chinese chess with my classmates.
Although Tom was ill,he went to school.
Where is Marry?She has gone to the cinema;
Have you been to Beijing ?Yes I have.
I used to play computer games,now I don"t do it.
