在下列条件中火星和地球最接近的是（）
A.重力加速度大小
B.公转周期长短
C.昼夜交替周期长短
D.表面温度高低
参考答案：C
When asked about his happiness, Baoqiang said that if he could afford _________ house, he would feel he was really _________ success.
A．/, a
B．/, the
C．a, a
D．a, /
在气相色谱法中，与含量成正比的是色谱峰的
A．保留体积
B．保留时间
C．相对保留值
D．峰高
E．峰面积
