问题 问答题 简答题

真正成熟的种子应具有什么特征?

答案

参考答案:

(1)营养物质发合成、运输已经停止,种子的干物质的积累不再增加;

(2)种子含水量减少,种子的硬度增强,对不良环境的抗性增强;

(3)种皮变坚固,呈现出种子固有的颜色和花纹;

(4)种子的生理成熟过程已经完成,具备发芽能力。

阅读理解

阅读理解。

     General Airport Tips

     Plan to get to the airport at least an hour early, or two during holidays and other busy times; this will

reduce the stress of the flight. If all goes well, you will have time to relax, shop for last-minute items, or

have a meal before the flight.

      Flight Delays

     Find out why your flight is delayed. Call the free call numbers. Find out if other airlines are experiencing

similar delays. If you believe the delay is due to something other than weather or air traffic problems, then

mention your suspicion (怀疑) and ask the airline agent to book you on the next available flight, either on the

same air-line or a competing one. This is called "Rule 240", and all airlines are required to do it. Use the lingo

(行话); ask,"Can you 240 me?" when speaking with an agent. They will know what you mean.

     Flight Cancellations (取消)

     If your flight is canceled, then make a reservation on the next flight to your destination. Usually, air-line

personnel will try to book everyone on their next flight out. Often they will put you on a competitor's next

flight only if you request it. If on-time arrival is important to you, when you check flights through our

reservation system you can rate your choices based on their on-time arrival records. Be sure to also check the

weather conditions, as they often affect flight schedules.

1. A person goes to the airport ahead of time mainly to _______.

A. buy what he wants in the airport

B. have a good rest in the airplane

C. reduce the pressure of the flight

D. get on the airplane immediately

2. If a person calls "Rule 240", he wants to _______.

A. change for the ticket to the next flight

B. make sure the time for the next plane

C. know if other flights' delays happen

D. ask the reason for the plane delay

3. After a flight cancellation, a passenger can_______.

A. arrive at his destination on time

B. be arranged on a competing flight

C. make sure the weather is quite fine

D. reserve the next flight to your destination

4. The purpose in writing this text is to________.

A. show us how to get on a plane

B. tell us what to do before and after a flight

C. put forward suggestions for a flight

D. teach us actions before an emergency

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