在图中作出人看到球的光路图．_爱下问搜题

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问题问答题

在图中作出人看到球的光路图．

答案

阅读理解

阅读下列短文，选择正确答案。

The U. S.'s flag is red, white and blue. It's the same colour as the U. K.'s and Australia's flag. It has fifty white stars, seven red stripes and six white stripes. People speak English in the U. S. The capital city of the U. S. is Washington, D. C.

1. People speak in the U. S.

A. Chinese
B. English
C. French

2. How many white stars on the U. S.'s flag?

A. Five.
B. Fifteen.
C. Fifty.

3. What colour are the stripes?

A. White.
B. Red.
C. Red and white.

判断题

异程式水系统管路简单，不需要同程管，系统投资较少，因而常在水系统规模较大时采用。