下列各对数中,互为相反数的是[ ]
A.+(-5.2)与-5.2
B.+(+5.2)与-5.2
C.-(-5.2)与5.2
D.5.2与+(+5.2)
答案:B
Last summer I took a course on ________ poisonous gases.[ ]
A.how to deal with
B.what to deal with
C.how to be dealt with
D.what to be dealt with
对润滑油的闪点和凝固点要求是()。
A、适宜
B、越高越好
C、越低越好
D、无要求