育龄期女性体温随月经周期发生变动,基础体温的最低点是在()
A.月经期开始
B.月经期结束
C.排卵前1周
D.排卵日
E.黄体期
参考答案:D
(2013·兰州市高三二模)Look at this year's sales figures ________ last year's; they're much better.
A.against
B.from
C.with
D.between
等离子弧焊时,其喷嘴高度增大,则电弧的熔透能力降低。