等离子弧焊时,若等离子气中加入适量的H2,则可增加()和提高();有利于提高生产率。
A.熔深
B.融合比
C.焊接速度
D.生产率
参考答案:A, C
Good afternoon, boys and girls. I’m Li Hong. I’m an English boy. Li Hong is my Chinese name. Look, this is a picture of my family. The tall man is my father. His name is Ken Martin. This is my mother, Sandy Jordan. Who’s that little girl? She is my sister, Lucy. Can you find me in the picture? I’m the boy in blue.
根据短文选择正确答案。
小题1:This is ________ family.
A.a Chinese
B.an English
C.a Japanese
D.an American小题2:There are ________ people(人)in the picture.
A.one
B.two
C.three
D.four小题3:________ is my father.
A.Sandy
B.Ken
C.Mrs. Martin
D.Mr. Jordan小题4:________ is my mother.
D.Mr. Jordan小题5:What color am I in? I am in ________.
A.brown
B.black
C.blue
D.red
工业场所有害因素职业接触限值是职业性有害因素的接触限量值,指劳动者在职业活动过程中( )反复接触对机体( )急性或慢性有害健康影响的允许接触水平。
A.长期;引起
B.长期;不引起
C.短期;引起
D.短期;不引起