唇的血供主要来自（）。 A.上颌动脉 B.面动脉 C.舌动脉 D.颞浅动脉 E.面横

根据下面短文内容，在短文的空格处填上一个恰当的词，使短文完整、通顺。

Do you often like to use disposable (一次性的) chopsticks when   小题1: in restaurants? It’s time to drop this habit.

China produces 80 billion pairs of disposable chopsticks every year. “This is enough to cover Tian’anmen Square 363 times,” said Bai Guangxin, chairman of Jilin Forest Industry Group.

“The production of such chopsticks is a heavy burden (负担) on national forests,” Bai added. People need to cut     小题2: over 20 million 20-year-old trees to make way for this production.

Many people choose to use disposable chopsticks     小题3:  they think that they are cleaner. However, many disposable chopsticks are not as     小题4:  as people think. Some may even be toxic (有毒的), China Daily reported.

Several days ago, actor Huang Bo posted a message on his micro blog. He wrote that when he tried to wash the disposable chopsticks in a restaurant, he was     小题5: to find that the chopsticks turned the water yellow and gave off a bad smell.

Some scientists said the color and     小题6:  of the chopsticks may show that they have something harmful such as sulphur (硫磺) and other chemicals (化学品). That’s bad    小题7:    people’s health.

As Bai Guangxin suggested, it’s better that people carry their own chopsticks around. It doesn’t just help save the environment; it also   小题8:  our own health.

观察临时装片时，视野里出现了污点，污点不可能在（　　）上．

A．物镜

B．目镜

C．装片

D．反光镜

实行出口退税制度，是指货物在报关出口后，凭有关凭证报送税务机关批准退还或免征（）

A、关税和所得税

B、增值税和所得税

C、消费税和关税

D、消费税和增值税

多巴胺舒张肾血管是由于（）

A.激动β受体

B.阻断α受体

C.激动M胆碱受体

D.激动多巴胺能受体

E.使组胺释放

电视照明电光源的有效寿命指的是（）。

A.不能工作时的全部累计点亮时间

B.光通量下降到不能工作时一定区间的时间

C.从开始点亮到其光通量下降到一定数值时的全部累计点亮时间

D.从开始点亮到其不亮时的全部累计点亮时间