4．正常人的褐眼(A)对蓝眼(a)为显性，一个蓝眼男子和一个其母是蓝眼的褐眼女子结婚。从理论上分析，他们生一个蓝眼男孩的几率是

A．75%　　　　 B．50%　　　　 C．25%　　　　　　 D．12.5%

3．豌豆的白花和紫花为一对相对性状。下列杂交实验中，能判定性状显隐性关系的是

①紫花×紫花→紫花 　　②紫花×紫花→301紫花+110白花

③紫花×白花→紫花 　　④紫花×白花→98紫花+107白花

A．①和③ 　B．②和③ 　　C．③和④ 　D．④和①

2．具有下列基因型的植物进行自花传粉，其后代会出现性状分离的是

A．AA　　 B．aa　　 C．Aa　　 D．AAbb

1．下列各对性状中，属于相对性状的是

A．狗的长毛和卷毛　　　　　　 　　B．羊的黑毛和兔的白毛

C．果蝇的红眼和果蝇的棒眼　　　　 D．人的有耳垂和无耳垂

9.(★★★★)Don’t come today.I’d rather you________ tomorrow.

　　es D.came

8.(★★★★)It was ordered that no parking________ allowed in front of the building.

　　 A.is B.be C.was D.would be

7.(★★★★)-He is a very brave man.

　　 -Yes,I wish I________ his courage.

　　 A.have B.had

　　 C.will have D.would have

6.(★★★★★)If you________ at school,you________a college student now.

　　 A.had studied hard;would have been

　　 B.should have studied hard;should have been

　　 C.had studied hard;would be

　　 C.would study hard;must have been

5.(★★★★)If only I________ their advice.

　　 A.follow B.will follow

　　 C.have followed D.had followed

4.(★★★★)Everything will go on as usual as if________ happened.

　　 A.nothing had B.anything hadn’t

　　 C.nothing was D.anything was not