A.HF的电子式:
B.乙醇的分子式:C2H6O
C.磷原子的结构示意图:
D.乙烯的结构式:H-C=C-H
答案:B
Some new teaching buildings ____ in Shunyi last year.
A.build
B.are built
C.built
D.were built
(二)
设备基础质量合格证明书有哪些