液化石油气属于（）。
A.永久气体；
B.高压液化气；
C.低压液化气；
D.混合气
参考答案：D
药理学
一You have made great progress in your studies of English，haven’t you?
一Yes，but much _______ ． ‘
A．remains to do
B．is remained to do
C．remains to be done
D．is remained to be done
