试分析内燃机进、排气门提前开启和迟后关闭的原因,其数值的大小与哪些因素有关?
This question ________ now is where to build the new factory.
A. discusses
B. discussing
C. be discussed
D. being discussed
We are delighted at the news ________ they have stated the business cooperation with your company.
A. that
B. when
C. which
D. what