题目

“移植物抗宿主病”是外源血液中的免疫活性细胞攻击受血者细胞而引发的并发症，输“全血”（血浆、红细胞和免疫细胞等）更易发病，输“成分血”（血液中提取的组分）可降低发病风险。红细胞无MHC分子，免疫细胞存在MHC分子。下列叙述正确的是（ ）A.正常受血者有相应抗体与异体同血型红细胞结合B.正常受血者的T细胞会启动对异体红细胞的细胞免疫C.正常受血者的T细胞会识别异体全血中免疫细胞的MHC分子并启动细胞免疫D.接受异体“全血”输 Many of us don’t pay attention to the importance of eye care. It’s said that if you take care of your body, then you can be healthy. That is why our eyes should be given a lot of care. Natural eye care should be put in a number one place. There are several causes leading to poor eyesight like not enough food, gene(基因) and aging(年龄增长). Televisions, computers and reading are also the causes of having poor eyesight. If you happen to work in front of the computer, it is best to take a rest every once in a while. Something dirty can cause redness and they will make you feel uncomfortable. It is bad for your eyes, too. If this happens, the best way is to clean your eyes by using cold water. You must also try your best to protect your eyes from harmful thing. For example, sunglasses are not just fashion but they can also serve as a great way to protect your eyesight from UV rays. Eating healthy foods will do good to your eyesight. Remember that vitamins(维生素) A、C and E are good for eyes. Try to eat food groups that have these vitamins. And you should do eye exercises because exercise protects your eyesight, too. If a person exercises regularly(规律地) and eats the right kind of food, his eyes will stay in good condition for a long time. All above are natural ways of eye care that help us keep healthy eyes. Being happy all the time can be helpful to a person’s eyesight, too. In a word, eye care is very important, no matter how old a person is. 1. __________ is the most important way to protect our eyes. A. Natural eye care     B. Taking medicine   C. Seeing the doctor     D. Being happy all the time 2. All the following causes can lead to bad eyesight except _________.    A. age               B. height            C. reading            D. computer 3. What should you do if you have to work in front of the computer?    A. Eat healthy foods.                      B. Clean the eyes by using cold water.    C. Wear a pair of sunglasses.                D. Have a rest after working for a while. 4. What do the under words “UV rays” mean?    A. 沙土             B. 闪电            C. 紫外线           D. 超声波  5. Which is the best title of the passage?    A. Ways of Eye Care                      B. Ways of Eye Exercises   C. Way of Being be Happy                  D. Way of Being Healthy