—Life now is not so easy as it _____ be, do you think so?

—Yes. I _____ working seven days a week to get more pay.[ ]

A. used to; used to  

B. was used to; used to

C. used to; am used to

D. was used to; am used to

选用不锈钢焊条时，主要应遵守与母材（）的原则。

A.等强度

B.等冲击韧度

C.等成分

D.等塑性