寿命表的编制依据是()。
A.粗死亡率
B.死因别死亡率
C.生存率
D.年龄别死亡率
E.疾病别死亡率
参考答案:D
解析:寿命表的编制依据是年龄别死亡率。
Experts have been warning _____ of the health risks caused by passive smoking.
A.at a time
B.at one time
C.for some time
D.for the time
低碳钢和Q235钢板对接时,焊条应选用( )。
A.E7015
B.E6015
C.E5515
D.FA303