Ⅰ、1、Welcome
2、What
3、There
4、are
5、labs
6、Are
7、any
8、are
9、there
10、where
Ⅱ、11-15：B B B A C
16-20：A B A C A
Ⅲ、21-25：B C D B D
Ⅳ、26、forty
27、really
28、The teacher's desk is in front of the blackboard
29、No，there aren't
30、Yes，he does