猪瘟弱毒冻干苗需要在（）条件下保存。
A、常温
B、-4℃
C、-15℃
参考答案：C
The mother was filled with _____ about her daughter's health,so she asked the doctor for help.
A．eagerness
B．anxiety
C．disappointment
D．fright
六月十日，A银行从B银行买入即期英镑500万，同时A银行卖给B银行1个月远期英镑500万，这是一笔（）交易
Ａ、套汇交易
Ｂ、套利交易
Ｃ、掉期交易
Ｄ、择期交易
