Why don’t you your teacher for help when you can’t finish it by yourself ?A. ask; writeB

问题补充：

Why don’t you your teacher for help when you can’t finish it by yourself ?

A. ask; write

B. to ask; writing

C. ask; writing

D. asking; write

答案：

A. ask; write

B. to ask; writing

(答案→)C. ask; writing

D. asking; write

解析：why don’t you do sth是固定句型结构意思是你问什么不…表示一种建议；finish doing sth表示完成某事也是固定句型结构。