your teacher will be pleased( )you finish your homework on time.A.if B,unles C,whether D,until

问题描述:

your teacher will be pleased( )you finish your homework on time.A.if B,unles C,whether D,until
选哪个,为什么,

A,表示条件“如果你能按时完成作业,你的老师会很高兴的”