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问题 单项选择题

药物从血液向中枢神经系统转运机制描述中，哪个是正确的

A．主要通过被动转运

B．主要通过主动转运

C．药物的非离子型分子透过细胞类脂质

D．离子型的药物向CNS转运极困难

E．一般说来，弱碱性药物容易向脑脊液转运

答案

参考答案：B

单项选择题 A1/A2型题

关于机体对肿瘤的免疫效应，不正确的是（）。

A.ADCC效应可以杀伤肿瘤细胞

B.Tc细胞杀伤作用需要MHC分子的限制

C.LAK细胞是由细胞因子活化的杀伤细胞

D.NK细胞杀伤作用不需要MHC分子的限制

E.补体不能杀伤肿瘤细胞
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单项选择题

Passage Two


Ask someone what they have done to help the environment recently and they will almost certainly mention recycling. Recycling in the home is very important of course. However, being forced to recycle often means we already have more material than we need. We are dealing with the results of that overconsumption in the greenest way possible, but it would be far better if we did not need to bring so much material home in the first place.
The total amount of packaging increased by 12% between 1999 and 2005. It now makes up a third of a typical household’s waste in the UK. In many supermarkets nowadays food items are packaged twice with plastic and cardboard.
Too much packaging is doing serious damage to the environment. The UK, for example, is running out of it for carrying this unnecessary waste. If such packaging is burnt, it gives off greenhouse gases which go on to cause the greenhouse effect. Recycling helps, but the process itself uses energy. The solution is not to produce such items in the first place. Food waste is a serious problem, too. Too many supermarkets encourage customers to buy more than they need. However, a few of them are coming round to the idea that this cannot continue, encouraging customers to reuse their plastic bags, for example.
But this is not just about supermarkets. It is about all of us. We have learned to associate packaging with quality. We have learned to think that something unpackaged is of poor quality. This is especially true of food. But it is also applied to a wide range of consumer products, which often have far more packaging than necessary.
There are signs of hope. As more Of us recycle, we are beginning to realize just how much unnecessary materials are collecting. We need to face the wastefulness of our consumer culture, but we have a mountain to climb.

What can we learn from the last paragraph

A．Fighting wastefulness is difficult.

B．Needless material is mostly recycled.

C．People like collecting recyclable waste.

D．The author is proud of their consumer cultur
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