与卵子激活有关的最主要离子是（）（1369-2）
A、Na+
B、K+
C、Ca2+
D、Mg2+
E、Zn2+
参考答案：C
—When can we see the movie “Avatar”? My patience _____.
—It has been on in our city so far.[ ]
A. has run out
B. has run out of
C. is running out
D. is running out of
工作温度低，宜选用粘度低的润滑油。
