某工程项目为全等节拍流水,且t=4,则K为()
A.1d
B.2d
C.3d
D.4d
参考答案:D
The twin sisters are______ a picture-book in their bedroom.[ ]
A. looking
B. watching
C. reading
D. seeing
热煨时必须向管内充热砂的是()。
A.不锈钢管
B.铜管
C.硬聚氯乙烯管
D.铝管