第三方存管投资者更换借记卡，每次换卡可选择（）证券公司。
A.一个
B.二个
C.三个
D.多个
参考答案：A
关于青蛙和家蚕的生殖和发育过程，下列说法不正确的是（ ）
A．它们都在水中完成发育
B．发育都是从受精卵开始的
C．它们都是变态发育
D．都要经过两性生殖细胞的结合
—_______ at this season of year in the north?
—It's much hotter than last year. The high temperature has lasted for days. [ ]
A. How are things going
B. How are you getting on
C. What's the weather like
D. What do you do
