吸尘是客房清扫的重要工作之一，在使用吸尘器前，首先应检查（）。A、部件是否完好B、是

一个物体自静止开始做加速度逐渐变小的加速直线运动，经过时间t，末速度为v_t，则这段时间内的位移 [ ]

A、x < v_tt /2

B、x = v_tt /2

C、x > v_tt /2

D、无法确定

振动沉管灌注桩属于（）。

A．挤土桩

B．非挤土桩

C．部分挤土桩

D．以上均不是

句型转换。

1. My uncle is forty-two years old. (对划线部分提问)

    _______ ________ is your uncle?

2. He likes watching TV very much. (改为否定句)

    He ________ _________ watching TV at all.

3. My little brother often does his homework at home on Sundays. (改为一般疑问句)

    _______ little brother often ________ his homework at home on Sundays?

4. She flies kites with her sister on Sunday. (用now替换时间状语on Sunday)

    She  ________ kites with her sister now.

5. His friend has one marker. (对划线部分提问)

   How ________ markers ________ his friend _______?

免税、减税等税收优惠可归为( )。

A．价格补贴

B．财政贴息

C．隐蔽性的财政补贴

D．企业亏损补贴

操作高压电器时，要（）、（）。