可比性、文学性是影响行研究的理论依据。
参考答案:对
She _____________ books every day. [ ]
A. read
B. reads
C. reading
请用化学用语填空:
(1)氮气_________
(2)单质锌_________
(3)甲烷 ___________
(4)硝酸根离子 _______