A:德国和法国
B:奥匈帝国和塞尔维亚
C:意大利和法国
D:奥斯曼帝国和塞尔维亚
(____)A. What's for dinner?
(____)B. What would you like?
(____)C. I'd like some beef, please.
(____)D. Would you like a knife?
(____)E. Pass me the bowl, please.
电火花计时器是一种使用____(填“交流或直流”)电源的计时仪器,当电源频率是50赫兹时,它每隔____秒打一次点.
下列关于植物激素的叙述,错误的是( )
—Excuse me, how long can I keep the book?
—You can return it by the end of this month.