问题 选择题

果农将桔子用塑料袋套上并拧紧口,可以延长保存期.利用的生物学原理主要是(  )

A.降低呼吸作用

B.提高呼吸作用

C.降低二氧化碳浓度

D.避免害虫破坏

答案

氧气:氧气是植物正常呼吸的重要因子,氧气不足直接影响呼吸速度,氧气少呼吸作用弱,氧气多,呼吸作用强.桔子进行呼吸作用需要消耗氧气,分解有机物,影响桔子的储存时间.根据氧对呼吸作用影响的原理,在贮存桔子时就降低氧的浓度,减少有机物的消耗,延长桔子的储存时间;果农将桔子用塑料袋套上并拧紧口,塑料袋内的氧气较少,抑制了桔子的呼吸作用,消耗的有机物较少,因此可以延长桔子储存的时间.

故选:A.

阅读理解

A Guide to the University

Food

The TWU Cafeteria is open 7am to 8pm. It serves snacks(), drinks, ice cream bars and meals. You can pay with cash or your ID cards. You can add meal money to your ID cards at the Front Desk. Even if you do not buy your food in the cafeteria, you can use the tables to eat your lunch, to have meetings and to study.

If you are on campus in the evening or lat at night, you can buy snacks, fast food, and drinks in the Lower Café located in the bottom level of the Gouglas Centre. This area is often used for entertainment such as concerts, games or TV watching.

Relaxation

The Globe, located in the bottom level of McMillan Hall, is available for relaxing, studying , cooking, and eating. Monthly activities are held here for all international students. Hours are 10 am to 10 pm, closed on Sundays.

Health

Located on the top floor of Douglas Hall, the Wellness Centre is committed to physical, emotional and social health. A doctor and nurse is available if you have health questions or need immediate medical help or personal advice. The cost of this is included in your medical insurance. Hours are Monday to Friday, 9am to noon and 1;00 to 4;30pm.

Academic Support

All students have access to the Writing Centre on the upper floor of Douglas Hall. Here, qualified volunteers will work with you on written work, grammar, vocabulary, and other academic skills. You can sign up for an appointment on the sign-up sheet outside the door two 30 –minute appointments per week maximum. This service is free.

Transportation

The TWU Express is a shuttle() service. The shuttle transports students between campus and the shopping centre, leaving from the Mattson Centre. Operation hours are between 8am and 3pm. Saturdays only. Round trip fare is $1.

小题1:What can you do in the TWU Cafeteria?

A.Do homework and watch TV

B.Buy drinks and enjoy concerts

C.have meals and meet with friends

D.Add money to your ID and play chess小题2:Where and when can you cook your own food?

A.The Globe, Friday

B.The Lower Café, Sunday

C.The TWU Cafeteria , Friday

D.The McMillan Hall , Sunday.小题3:The Guide tells us that the Wellness Centre  _________.

A.is open six days a week

B.offers services free of charge

C.trains students in medical care

D.gives advice on mental health小题4:How can you seek help from the Writing Centre?

A.By applying online

B.By calling the centre

C.By filling in a sign-up form

D.By going to the centre directly小题5:What is the function of TWU Express?

A.To carry students to the lecture halls.

B.To provide students with campus tours

C.To take students to the Mattson Centre.

D.To transport students to and from the stores.

多项选择题