对于脱甲烷塔，甲烷/氢比值越小，塔顶尾气中乙烯损失越小。
参考答案：错
He is getting fat, ________ he has decided to go to work on foot. [ ]
A. so
B. though
C. because
D. and
在显微镜下观察精子和卵子，卵子能运动，精子不能运动。 [ ]
