问题 问答题 简答题

简述种子品质及其指标:

答案

参考答案:

1)净度:纯净种子的重量占供检种子重量的百分比。

2)千粒重:在气干状态下,1000粒纯净种子的重量。测定方法:百粒法、千粒法、全量法。

3)种子含水量(种子含水率):种子中所含水分的重量占种子重量的百分比。

4)种子发芽能力:发芽率:在最适宜发芽的环境条件下,在规定的期限,正常发芽的种子数占供检种子总数的百分比。发芽势:种子发芽数达到高峰时的正常发芽种子的总数与供测种子总数的百分比。平均发芽速率:种子发芽所需的平均时间。场圃发芽率:在场圃的环境条件下,所测得的发芽率。

5)种子生活力:种子发芽的潜在能力。

6)种子优良度:人为的直接观察来判断种子的品质指标。种子的形态、色泽、气味、硬度等。解剖法、挤压法

选择题
阅读理解

Dear iPhone 4 Users,

The iPhone 4 has been the most successful product in Apple’s history. It is the best smartphone ever, and most users have told that they love it. So we were surprised when reading reports of reception (信号接收) problems, and we immediately began researching them.

To start with, holding tightly(紧紧地)almost any mobile phone in certain ways will reduce its reception by 1 or more bars of signal strength. This is true of iPhone 4, iPhone 3GS, as well as many other phones. But some users have reported that iPhone 4 can drop 4 or 5 bars when tightly held in a way. This is a far bigger drop than normal, and as a result some have said the iPhone 4 has a faulty antenna(天线) design.

Upon research, we find that the formula(公式) we use to calculate how many bars of signal strength to display is totally wrong. Our formula usually mistakenly displays 2 more bars than it should for a given signal strength. The big drop in bars is because the high bars were never real in the beginning.

We will give a free software update to correct the formula. This software update (软件升级)will also be available for iPhone 3GS. If you are not fully satisfied, you can return your undamaged iPhone to any Apple Retail Store or the online Apple Store within 30 days of buying and get all your money back.

Thank you for your patience and support.

Apple

小题1:The iPhone 4 drops more bars than normal when tightly held because of          .

A.a wrong antenna design

B.wrong usage

C.weak signal strength

D.a wrong formula小题2:How many more bars does the iPhone 4 show than it should for a given signal strength?

A.2

B.3

C.4

D.5小题3: What can we learn from the text?

A.The software update is fit for all cellphones produced by Apple.

B.The iPhone 4 has been the most successful product in history.

C.If a user is not satisfied with his iPhone 4, he will get ten times his money back.

D.The Apple company didn’t expect the reception problems of iPhone 4.小题4: The text is a letter          .

A.from Apple about iPhone problems

B.to Apple about iPhone 4 problems

C.to introduce the new iPhone 4

D.on how to pay back buyers for the faults