求下面7道英语题的答案、急、

求下面7道英语题的答案、急、
1、small sailboats can easily turn over in the water,____they are not managed carefully.
A.though B.before C.until D.if
2.___he referred to in his article was unknown to the general reader.
A.That B.What C.Whether D.Where
3.the traditional view is ___we sleep because our brain is prgrammed to make us do so.
A.when B.why C.whether D.that
4.it is difficult for us to learn a lesson in life___we've actually had that lesson.
A.until B.after C.since D.when
5.choosing the right dictionary depends on___you want to use it for.
A.what B.why C.how D.whether
6.last week,only two people came to look at the house ,___wanted to buy it .
a.none of them b.both of them c.none of whom d.neither of whom
7.many of them turned a deaf ear to his advise,___yhey knew it to be valuable.
a.as if b.noe that c.even though d.so that

DBDAADC
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