下列哪种金属在常温下即可蒸发,污染作业环境,引起职业中毒
A.铅
B.汞
C.锰
D.铁
E.铝
参考答案:B
解析:汞在常温下即能蒸发。因为其熔点为-38.9℃。
The witnesses ________ by the police just now gave very different descriptions of the fight. (2013·陕西,14)
A.questioned
B.being questioned
C.to be questioned
D.having questioned
生物种类繁多,主要包括______、______ 和微生物等类群.微生物主要由______、______ 和______等组成.