引起刀闸接触部分发热的原因有哪些（）。 A.压紧弹簧或螺丝松劲 B.在拉合过程中，电

Do you still remember the key points that _______ in his report? I don’t remember them all.

A．referred to

B．were referred

C．he was referred to

D．were referred to

The ________ look on her face suggested that she ________ it. [ ]

A. puzzling; hadn't expected

B. puzzled; hadn't expected

C. puzzling; wouldn't expect

D. puzzled; shouldn't expect

离心泵密封环泄露损失的漏失量大小取决于叶轮口环的直径、间隙的大小和两侧的（）。

A、结构

B、空间

C、压差

D、温度

制冷剂在蒸发器中吸热气化的过程中，它的比容逐渐（）的。

A．增加

B．减少

C．不变

D．无法确定