由于横道图比较法以()计划为基础,因而带有不可克服的局限性。
A、横道
B、网络
C、工程
D、工期
参考答案:A
You ________ in person; a telephone would have been enough.
A.couldn’t have come
B.needn’t have come
C.shouldn’t have come
D.mustn’t have come
叙述角形调节阀的特点。