Today is Sunday, March 20. We, sixteen boys and seventeen girls, go to school early, but we have no lessons. Our teacher takes us to the zoo. We are very excited about the trip. We get on a bus, it goes fast and at half past nine we get there. How beautiful the zoo is! There're a lot of trees, some hills, and a big lake. The sun is shining and the flowers are coming out. There are all kinds of animals in it, elephants, monkeys, birds, fishes and many other animals. The birds are singing in the trees and the fishes are swimming in the lake. We like to watch monkeys. They are playing on the hill or having oranges, apples and bananas. There are many rules in the zoo. We mustn't do this and we mustn't do that. But we all have a good time. At one in the afternoon we leave the zoo. 

小题1: The weather is ______ today

A．sunny

B．cloudy

C．rainy

D．windy小题2: _______ students and a teacher go to the zoo by bus

A．Sixteen

B．Seventeen

C．Thirty-three

D．Thirty -four小题3:We stay in the zoo for ____ hours.

A．four and a half

B．three and a half

C．four

D．five

( )控制的伺服系统在性能要求较高的中、小型数控机床中应用较多。

A．闭环

B．半闭环

C．双闭环

D．开环