12. Mercury, one of the deadliest toxins, makes up approximately fifty percent of the amalgam used by dentists in sliver fillings. The effects of acute mercury poisoning are known-kidney failure, muscle tremors, memory loss, and even death. It is clear (结论标志词) that responsible dentists should remove all of the patients silver fillings and replace them with filling of plastic composites.
Which of the following, if true, most strengthens the author's argument?
(A) Sliver fillings gradually corrode and small amounts of mercury leak from the amalgam.
(B) It is difficult to measure the amount of mercury in a person's body.
(C) Some patients have more than one filling per tooth.
(D) Mercury poisoning produces a range of subtle but distinctive symptoms.
(E) The materials for plastic composite fillings are readily available to dentists.
为什么不选E呢?
结论中提到了塑料的filling,但是A没有涉及啊。
另外,文中也没有提到水银是装在银里面的,只说含有50%的水银,很有可能直接露在外面,漏不漏照样会中毒。这不是要求题外的常识吗?
请NN指教,谢谢! |