29. By the time he gets home, his father ______ for Paris on business.
A. has left B. will have left C. had left D. will leave
28. __________, you’ll never be able to persuade him.
A. No matter how good advice you give B. However good advice do you give
C. No matter what good you give advice D. Whatever good advice you give
27. We all know that, _____ , the climate change will get worse.
A. not if dealt carefully with B. if not carefully dealt with
C. if dealt not carefully with D. not if carefully dealt with
26. The engine of the ship was _____ and the bad weather ____ the helplessness of the crew at sea.
A. out of order; added to B. beyond reach; put to
C. in place; turned to D. under control; led to
25. Even today I still remember the great fun we had ______ games on the beach in those happy days.
A. play B. to play C. playing D. played
24. Was it in the village _____ we used to live in ____the accident happened?
A. where; that B. which; that C. that; where D. where; which
23. As they are retired, Mr. and Mrs. Scott prefer a house in the country to spend their late years to ______ in a large city.
A. which B. it C. one D. that
22. Due to bad weather, the police had to ______ the search for the missing boy.
A. resign B. abandon C. conduct D. release
21. ---I’m sorry I can’t accept ______ price offered.
---Well, I’m sure you can’t find ______ better bargain.
A. the; a B. a; the C. a; a D. the; the
36.
(10分)已知果蝇刚毛和截毛这对相对性状由X和Y染色体上一对等位基因控制的,刚毛(B)对截毛(b)为显性;控制果蝇的红眼和白眼性状的基因只存在于X染色体上,红眼(R)对白眼(r)为显性(如右图所示)。果蝇的性别常常需要通过眼色来识别。
(1)若只考虑刚毛和截毛这对性状的遗传:
① 果蝇种群中雄果蝇的基因型除了有XBYB(如图所示)和XBYb外,还有 ;
② 现将两只刚毛果蝇杂交,子代雌果蝇中既有刚毛,又有截毛,雄果蝇全为刚毛,则这两只果蝇的基因型是 ;
③ 若②中子代中有一只XXY的截毛果蝇,分析其变异的原因时发现:只可能是由某亲本形成配子时,在减数第二次分裂中染色体分配异常造成。那么,其双亲的基因型是 。
(2)种群中有各种性状的雌果蝇,现有一只红眼刚毛雄果蝇(XR_Y_),要通过一次杂交实验判定它的基因型,应选择 雌果蝇与该只果蝇交配,然后观察子代的性状表现。
① 如果子代果蝇均为刚毛,则该雄果蝇基因型为XRBYB;
② 如果子代
;
③ 如果子代
。
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