4. It can be inferred from the passagethat if the prostaglandin synthetase is only partially blocked, which of thefollowing is likely to be true? (A) Some endorphins will be produced, and some pain signals will be intensified. 被加强,很荒谬,endorphin是大脑自带的减痛剂,所以intensified与原文相反。 (B) Some substance P is likely to be produced, so some pain signals will reachthe brain.正确,因为一部分prostaglandin被阻止,那么会有一部分painsignals(由prostaglandin产生的)可能会到达spinalcord 产生substance P,P会激活周围的细胞,传递电讯号给大脑。 (C) Some sodium ions will be blocked, so some pain signals will not reach thebrain. Sodium ions被阻止,确实有阻断pain signals到达brain的功效。但是,这个不是prostaglandin起的作用,而是novocaineand xylocaine起的作用。 (D) Some prostaglandins will be produced, but production of substance P will beprevented.看下面的分析就明白了,一部分prostaglandins被阻止,但是pain signals继续传递,并且题目没有说pain signals被novocaineand xylocaine 阻断了,没有到达spinal cord.所以有可能产生了substance P. (E) Some peptides in the brain will receive pain signals and begin to regulateincoming pain traffic. 文中说endorphin是peptides一种, E范围有点过大,而且文中是说endorphin的作用,不是全部peptides的作用。再有,它的作用是block不是receive.