Every one _______ an English story book. [ ]
A. have
B. are having
C. has
答案:C
“西气东输”工程中的“气”是指天然气,其主要成分是甲烷(CH4)。下列有关“CH4”的意义认识不正确的是[ ]
A.
B.
C.
D.
什么是远景储量?