一般说来,液体燃料的比重越小,闪点怎样变化?()
A.闪点越低
B.闪点越高
C.自燃点高
D.自燃点低
参考答案:A
恙虫病治疗首选()
A.氯霉素
B.磺胺
C.青霉素
D.庆大霉素
E.红霉素
The house is finished at last. All their hard work has ________.
A.paid back
B.paid up
C.paid off
D.paid for