下列关于尖叶菠菜生物学特性正确的是
A、耐热力较强
B、耐寒不耐热
C、对日照长短不敏感
D、对日照长短较敏感，在长日照下抽薹快

If you are writing or studying, it makes very much diff...

单项选择题If you are writing or studying, it makes very much difference where the light comes from. People who use books and pens every day have to be especially careful about the way the light shines on their work.
Every house gets its light either from daylight through the windows--which is the best to use--or from lamps or electricity; but whichever kind of light it is, the way it shines toward our book or work is a matter of great importance to the eyes.
Take a book, sit with your back toward the window, and try to read. Your shadow(影子) falls all over the page and makes it almost as bad for your eyes as if you were in a dark room. Now turn around and face the window. The page is in the shadow again, while the bright light is in your eyes.
Try sitting with your right side toward the window. This is very well for reading, but if you were writing, the shadow of your hand would fall across the page and bother(打搅) you a little.
There is just one other way:sit with your left side to the window. Now everything is perfect for reading and for writing, too.
Whatever kind of light is in the room, the rule about the right to sit is always the same.
Which of the following is true?

康德通过什么将理论哲学和实践哲学沟通起来？（ ）A.图型 B.自然的合目的性C.理念 ...

单项选择题康德通过什么将理论哲学和实践哲学沟通起来？（ ） A. 图型 B. 自然的合目的性 C. 理念 D. 规定性判断力

Life gets noisier every day and very few people can fre...

单项选择题Life gets noisier every day and very few people can free from noise of some sort or another. It doesn′ t matter where you live--in the middle of a modern city, or a faraway village--the chances that you will be disturbed by jet aero planes, transistor radios, oil powered engines, etc. , are almost everywhere. We seem to be getting used to noise, too. Some people feel quite lonely without back-ground music while they are working.
Scientific tests have shown that total silence can be very frightening experience for human beings. However, some people enjoy listening to pop music which is very loud, and this can do harm to their eardrums(耳鼓). The noise level in some disco is far above the usual safety level for heavy industrial areas.
One recent report about noise and concentration(专心,) suggested that although a lot of people say that any noise disturbs their concentration, what really affects their ability to concentrate is a change in the level of noise. It goes on to say that a background noise, which doesn′ t change too much (music, for example) lnay even help people to concentrate.
Scientists have discovered that what prevents people from concentrating is