1. —May I open the window to let in some fresh air ?—A. Come onB. Take careC. Go ahead!D.

问题补充：

1. —May I open the window to let in some fresh air ?

—

A. Come on

B. Take care

C. Go ahead!

D. Hold on!

答案：

A. Come on

B. Take care

C. Go ahead!

D. Hold on!

解析：

Come on 来吧，走吧；Go ahead可以，干吧，开始，进行；Take care 小心，当心 Hold on 握住不放，坚持。