（ ）15. To be a good swimmer, I must have _____ lessons.
A. swim B. swimming C. to swim D. swims
（ ）16. —Let’s play basketball on Sunday. —_____.
A. That’s a great idea B. You’re welcome
C. That’s right D. That’s all right
（ ）17. —What day is it today? —_____.
A Monday B. fine C. sunny D. May 1