下载APP
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】图1 轴系结构示例2、 如图1所示轴系结构，假设所有的圆角半径合适。以下对序号7处描述正确的是（ ）。
A.
正确，需要轴肩结构以定位轴承；
B.
错误，应该增加轴肩与轴承接触，且低于轴承内圈高度。
C.
错误，应该增加套筒来定位轴承，且套筒高度低于轴承内圈；
D.
错误，轴肩结构多余；
【单选题】Compared with their cosmologist(宇宙学家) colleagues, cosmogonists(星源学家) can sound a little old-fashioned. Edgar Allen Poe turned to the mysteries of cosmogony in an 1848 public lecture, just reprinted by...
A.
cosmogonists have more disagreements about the distant outer space
B.
astronomers have already obtained full knowledge about Uranus and Neptune
C.
there exist a lot of mysteries for cosmogonists in inner space
D.
cosmogonists are often reluctant to go home for the existence of deeper family mysteries