问题 填空题

带火星的小木条伸到盛有氧气的集气瓶中会______.实验室常用KClO3和MnO2混合加热来制取氧气,在此反应中MnO2起______作用.

答案

氧气具有支持燃烧的性质,能使带火星的木条复燃复燃,因而常用此法来检验或验满氧气.在实验室用KClO3和MnO2混合加热来制取氧气,在此反应中MnO2加快了氯酸钾的反应速率,做催化剂,因而在此反应中MnO2起 催化作用.

故答案为:

复燃(重新燃烧);催化.

单项选择题
阅读理解

阅读理解。

     The Los Angeles Zoo has many public programs that aim to teach the public about animals and natural

protection.

Safari shuttle (旅游电车)

     While you're here, take the Safari shuttle for a quick trip from one end of the Zoo to the other. All day

long, seven days a week (from 10 am to 5 pm), the Safari Shuttle picks up passengers, circles the Zoo, and

returns to the main flamingo (火烈鸟) exhibit near the front entrance. You can get on and off the shuttle as

often as you like.

Food

     Safari Café (at the Zoo entrance) offers Starbucks coffee, fresh-baked cookies, and ice cream. Gorilla

Grill is the spot for toasted food, kids' meals, snacks, and ice cream. La Casita serves a variety of Mexican

food and refreshments (甜点). Silverback's Cafe offers sandwiches, salads, bread bowls, cold beer, and

refreshments.

Hour

     The Zoo is open from 10 am to 5 pm every day of the year except Christmas Day. Special summer long

hours are until 6 pm. from July 1 to September 7. Please remember, the Zoo starts putting animals in for the

night at 4 pm during regular hours, and at 5 pm. during summer hours. Admission Prices (票价)

     Adults (aged 13 and above): $ 9

     Seniors (aged 62 and above): $ 6

     Children (aged 2 to 12): $ 4

     Children (under 2): free

Items Not Allowed on Zoo Grounds

     Alcohol, Glass bottles, Pets, Bicycles, Skateboards, and In-line skate.

     If you are planning a picnic while visiting the Zoo, please do not bring any glass items or other things that

are easy to break. Also for the safety of the animals, no plastic bags are allowed within the Zoo.

1. Which of the following provides kids' meals? [ ]

A. Safari Café.

B. Gorilla Grill.

C. La Casita.

D. Silverback's Café.

2. People can see all the animals at the Los Angeles Zoo at ______. [ ]

A. 11 am. on Christmas Day

B. 4:30 pm. on May 5

C. 3 pm. on March 5

D. 6 pm. on September 7

3. How much does it cost if a couple with their one-year-old twins visits the Los Angeles Zoo? [ ]

A. $18.

B. $26.

C. $22.

D. $17.

4. When visiting the Los Angeles Zoo, people can ______. [ ]

A. ride a bike through the Zoo

B. have a picnic on the Zoo grounds

C. take food with plastic bags

D. take their pets along