当螺杆式压缩机转子转动时,一对相互啮合的槽沟相通,表明转子进入()状态。
A.吸气
B.压缩
C.封闭
D.排气
参考答案:B
We all love our English teacher, He always makes his English class very ________.
A.interest
B.interests
C.interesting
D.interested
下图为关于某遗传病的家族系谱图(基因用B和b表示)。请据图回答:
图中4号的旁系血亲有()