与巨幼红细胞性贫血有关的是()
A、尼克酸
B、叶酸
C、维生素C
D、维生素B12
参考答案:B, D
The H1N1 flu, often _____ “swine flu” by the public media, is a disease which can be prevented, controlled and cured.
A.calls
B.to call
C.calling
D.called
光功率测量值以下哪些在正常范围之内()
A.0db
B.-10db
C.-20db
D.-30db