VHF收/发转换时间应（）。 A.≤10ms B.≤20ms C.≤30ms D.≤

阅读理解。

     Shopping in Singapore is really a pleasure for tourists. The Great Singapore Sale is held every year, usually

during the summer months. Singapore's famous shopping stores welcome a great number of visitors from all

over the world. Their shopping hours last till midnight. During this time, nice and cheap goods are on sale for

tourists to choose from. Tourists can also try delicious foods there and experience the Singaporean nightlife.

     Certain stores offer discounts (折扣) of up to 70 percent or even higher if people use their credit cards. For

tourists that hold a special Tourist Card, they can enjoy a lot of benefits (好处), such as discounts on watches,

jewellery and cosmetics (化妆品). The card also gives discounts when you visit local attractions such as the

Singapore Zoo.

     It is well worth checking out in the different shopping districts of Singapore during this 8-week Shopping

Marathon. Orchard Road is surely the best place for shopping in the city. A large number of restaurants, clubs

and cafes can be found in this area. Marina Bay includes both big department stores as well as small shops, so

everything you would want to buy can be found here.

     Advice for tourists planning to enjoy this festival of shopping: travel light and take a comfortable pair of

shoes with you, for you are sure to do a lot of walking and return with your bags much heavier.

1. You probably see the Great Singapore Sale when you go to Singapore in _____.

A. January

B. August

C. May

D. November

2. We can learn from the passage that _____.

A. the Great Singapore Sale is held twice each year

B. the Shopping Marathon lasts for more than two months

C. Orchard Road is Singapore's best shopping street

D. Marina Bay is a narrow street with small shops

3. Why are tourists advised to travel light if they want to enjoy the shopping festival?

A. They will buy many goods and have to do lots of walking.

B. It is not safe for them to take heavy bags with them.

C. There is heavy traffic in the shopping districts of Singapore.

D. Travelling with too many things is not allowed in Singapore.

4. The author wrote this passage mainly to _____.

A. tell readers his or her experience and impression of visiting Singapore

B. help readers find the best shopping centres in Singapore

C. explain what has made Singapore popular around the world

D. introduce shopping in Singapore and attract more readers to go shopping there

大型空分装置中以（）为冷却效果好，等温效率高，最理想的压缩机。

A、水平剖分式离心压缩机

B、等温型离心压缩机

C、筒型离心压缩机

D、等温活塞压缩机

与溴化钾同服，会生成有剧毒的溴化汞或碘化汞的是（）。

A.石膏

B.朱砂

C.虎杖

D.含碱性成分的中药

E.黄药子

在做水文调查时，以下做法正确的是( )。

A．收集为主，只有在资料不足时才进行一定的实测

B．实测为主，收集的资料只是作为补充

C．收集现有资料就可以

D．收集资料和实测并重

一种语言中不同种类的变量往往采用不同的存储分配策略，C语言中的全局变量和静态变量采用静态分配，而自动（Auto）类变量采用（）。

A．最佳分配

B．首先分配

C．堆式分配

D．栈式分配