组成装配尺寸链至少有增环,减环和().
A、组成环
B、环
C、封闭环
D、装配尺
参考答案:C
The thirteen stars on the flag _ the thirteen colonies that announced independence first.[ ]
A. are
B. sign
C. represent
D. compare
导致肾病综合征复发及疗效不佳的主要原因是()
A.肾功能不全
B.动脉粥样硬化
C.肾静脉血栓
D.下肢静脉血栓
E.感染