把影响某一装配精度的有关尺寸，彼此按顺序连接起来，可形成一个封闭图形，所谓装配尺寸链就是指这些相互关联尺寸的总称。
参考答案：对
The scientists are making further research to develop more advanced rockets________spaceships can be launched. [ ]
A. which
B. with which
C. /
D. with that
试写出蚕豆根尖微核的识别标准。
