问题
单项选择题
工件定位时，常需要限制多个自由度，若采用一个表面定位不能满足加工要求时，常需要（）表面定位，这种定位方式称为组合定位。
A.五个
B.四个
C.三个
D.两个或两个以上
答案
参考答案：D
搜题请搜索小程序“爱下问搜题”
工件定位时，常需要限制多个自由度，若采用一个表面定位不能满足加工要求时，常需要（）表面定位，这种定位方式称为组合定位。
A.五个
B.四个
C.三个
D.两个或两个以上
参考答案：D
| 完形填空。 |
| Last Sunday morning, Yang Ling, Helen and I ① to a supermarket to ② shopping. Suddenly I ③ a thin man beside a woman. He ④ her purse ⑤ her bag and then ran out ⑥ the supermarket. I ⑦ Yang Ling and Helen to ⑧ ll0. I ran after the man and shouted. "Stop thief! Stop thief!" The thief ⑨ me and ran faster. Some people helped me to run after the thief. At that time, a police wagon (警车) came and ⑩ the thief. "Great, Liu Tao !" A police officer said to me. |
| （ ）①A. go （ ）②A. do （ ）③A. see （ ）④A. stole （ ）⑤A. to （ ）⑥A. of （ ）⑦A. tell （ ）⑧A. call （ ）⑨A. hear （ ）⑩A. catch | B. are going B. did B. saw B. is stealing B. with B. from B. telled B. calling B. heared B. caught | C. goes C. does C. seeing C. steals C. from C. to C. told C. calls C. heard C. catches | D. went D. doing D. sees D. steal D. to D. at D. telling D. called D. hearing D. to catch |