问题是这样的sc prep 2 34题
Besides adding complementary flavors to many foods, hot sauces stimulate the release of endorphins in the brain, just as exercise does, and these have a pain-relieving effect like morphine's.
(A) hot sauces stimulate the release of endorphins in the brain, just as exercise does, and these have a pain-relieving effect like morphine's
(B) hot sauces stimulate the release of endorphins in the brain, like exercise, and they have a pain-relieving effect that is like morphine
(C) hot sauces and exercise both stimulate the release of endorphins in the brain, and they have a pain-relieving effect like morphine
(D) the release of endorphins in the brain is stimulated both by hot sauces and exercise, and they have a pain-relieving effect like morphine's
(E) the release of endorphins in the brain is stimulated by hot sauces, just as with exercise, and these have a pain-relieving effect like that of morphine
选a 但是不明白的地方是 and these have a effect。。。these在这里指代什么呢。BY语法里不是说these that 等词是不能单独做主语的吗？要和名词一起用才有意义such as: that boy
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