How many_____are there in your class?
A. Germen
B. Canadian
C. American
D. Japanese
Can you see nine _____ in the picture?
A. sheep
B. dog
C. horse
D. chicken
Translate the passage into English, using the words and phrases given below.a couple of ; keep in touch with; come up; neighborhood; on one's mind; keep up; correspondence和远方的朋友保持联系不是一件容易的事。对我来说,情形就是这样。离开旧街区和那里的朋友们已有几年了。我一直打算给他们写信,可是总有这样那样的事,似乎就是抽不出空。但是我一直记挂着他们,我想我今后也一定会努力与他们保持通信联系的。
负荷持续率是指一个工作周期内______与______的百分比值;尖峰电流是指持续时间1-2秒的短时______。