Researches show what we already suspected: Three out of four babies who died of SIDS(婴儿猝死)

Researches show what we already suspected: Three out of four babies who died of SIDS(婴儿猝死) involved co-sleeping. We’ll say it again. The safest course is not to sleep with babies.
We know the argument: Bad parenting, not co-sleeping, is to blame for the dozens of babies’ deaths. Some parents stick to co-sleeping because it helps them bond with their newborns. They say those who give co-sleeping a bad name either had been drinking, used drugs or were too tired to notice that they rolled over on their children.
But, most of the cases did not involve drugs or alcohol. There’s a “but” here, however. Submitting to a test for drugs or alcohol in these cases is voluntary, so it’s difficult to know with certainty.
Organizations like the Black Health Coalition and others have explained the safe way to co-sleep. While we understand those arguments, we also know that mistakes can happen and that it only takes one time for something to go terribly wrong. The risk outweighs the benefit.
In all likelihood, parents will continue to co-sleep, and some will do so without ever having an incident, but babies are too vulnerable(易受伤的) for parents to take such chances. Therefore, the best place for babies to sleep is in their own beds, on their backs, with no pillows, blankets or toys. No parent wants a tragedy(悲剧) to occur. The best way to make sure the tragedy doesn’t happen is to allow babies to sleep alone in their own cribs(摇篮).                                         
【小题1】According to the author, most of the SIDS cases happened because of     .A．drugs B．co-sleepingC．drinkingD．bad parenting【小题2】Some parents think sleeping with their babies can     .A．keep the babies healthyB．give co-sleeping a good nameC．prevent themselves from drinkingD．develop a good relation with their babies【小题3】The author holds the opinion that     .A．parents can sleep with babies, but cautiouslyB．co-sleep helps to bring babies closer to parentsC．parents can’t take chances to sleep with their babiesD．accidents only happen to those careless parents【小题4】Which of the following best describes the structure of the text?A．①B．①②C．①D．①↙↘                                   ↓                  ↙↓↘              ↙↓↓↘
②③④                  ③④                 ②③④           ②③④⑤
↘↙                                  ↓                  ↘↓↙
⑤                            ⑤                  ⑤B