American doctors say that mothers who smoke cigarettes before their babies are born may sl

American doctors say that mothers who smoke cigarettes before their babies are born may slow the growth of their babies’ lungs. They say reduced lung growth could cause the babies to suffer breathing problems and lung diseases later in life. Doctors in Boston studied 1,100 children. The mothers of some of the children smoked, the other mothers did not. Doctors found that the lungs of the children whose mothers smoked were 8% less developed than the lungs of the children whose mothers did not smoke, and that the children whose mother smoked developed 20% more cold and breathing diseases than other children later in life.
Another recent study found that children had a greater chance of developing lung cancer if their mothers smoked. The study also showed that the danger of lung cancer increased only for sons and not for daughters, and that the father’s smoking did not affect a child’s chance of developing lung cancer
49. Whose baby would have breathing diseases?
A.Mother who smokes cigarettes after their baby are born
B.Mother who smokes cigarettes before their baby are born
C.Mother who don’t smoke at all
D.Mother whose mother smokes
50. Suppose John’s father was a heavy smoker, so was Mary’ mother. According to this study, .
A. John is more likely to develop lung cancer B. Mary is more likely to develop lung cancer
C. Mary and John have the same chance to develop lung cancer
D. Neither John and Mary has the chance to develop lung cancer
51. This passage is to .
A. warn us of the danger of smoking before children.
B. warn people with breathing problems not to smoke.
C. warn us that mothers who smoke may affect their children’s health.
D. warn us that fathers who smoke may affect their children as mothers49---51 BBC

(答案→)49---51 BBC 解析：可联系答.案.网客服索取。

我明天再问问老师，叫他解释下这个问题