How, How many, How much, How long, How far，How fast, How often 等用法

一、构成特殊疑问句（注意主、谓语颠倒现象）

1. How is mercury different from silver? 水银和银有何不同？
2. How long have you worked at the airport? 你在机场工作多久了？
3. How many pandas are there in China? 在中国有多少熊猫？
4. How much of China's surface is covered with green plants? 中国表面（积）有多大比例为绿色植物所覆盖?
5. How much (money) should I pay for this pair of sun glasses? 这副太阳镜我该付多少（钱）？

注：how many 用于可数名词，而 how much 用于不可数名词。

1. How far is the Internet information center away from here? 因特网信息中心离这里有多远？
2. How fast is he driving the car? 现在他开车的速度有多快？
3. How often do you have access to the web site? 你隔多久访问这个（万维）网站？
4. How long will it take to reach the supermarket? 到达超市要花多长时间？
5. How high (或 tall) is your apartment building? 你们的公寓楼有多高？

二、构成主语从句、宾语从句、表语从句和同位语从句，但从句内主、谓语词序不颠倒

1. It is clearly known how they learn English. 他们如何学英语是清楚知道的。（主语从句，it 是形式主语）
2. The question is how much one cubic meter of air weighs under normal conditions. 问题是在标准情况下，一立方米空气重多少。（表语从句，试与上面第 5 句比较主、谓语词序。）
3. I didn't know how many English words you had learned for two years. 当时我不知你们两年学了多少英语单词。（宾语从句）
4. He answered the question how volume is affected by temperature. 他回答了温度如何影响体积这个问题。（the question 的同位语从句）
5. Can you answer us the question of how fast the molecules move? 你能回答我们分子运动有多快的问题吗？（介词 of 的宾语从句）

三、疑问词与动词不定式构成短语常顶一个名词

1. I do not know how to operate this new-type portable computer? 我不知如何操作这种新型手提式计算机？（作宾语）
2. How many experiments to perform a day is still a question. 一天做多少项实验还是一个问题。（作主语）
3. What do you know about how to send an-email? 关于如何寄发电子邮件，你知道什么呢?（常顶一个名词作介词 about 的宾语。）