下列常见的物理量，正确的是（） A．人体正常体温约为37℃

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问题选择题

下列常见的物理量，正确的是（　　）

A．人体正常体温约为37℃左右

B．光在真空中的传播速度是340m/s

C．通过家用照明灯的电流可达5A

D．刚刚能引起听觉的声音强度为50dB

答案

答案：A

阅读理解

读一读，判断正(√)误(×)。

Look! Who is sleeping (睡觉)? Oh, it's my cat, Mimi. Mimi is my good friend. She likes fish and milk

(牛奶). She has two big eyes and a small nose. She has white hair. She is very happy everyday. She is very

lovely (可爱的).

( ) 1. Mimi is not sleeping.

( ) 2. Her favourite food is fish.

( ) 3. She has a big nose.

( ) 4. Mimi is a white cat.

( ) 5. Mimi is happy.

问答题简答题

何谓金属的机械性能？具体有哪些性能？