— Who were those people with the flags?

用所给词的适当形式填空。

1. We spend an hour ________ (do) housework.

2.  I watched him________ (play) when I was 10.

3.  When I________ (be) seven, I ________ (start) learning skating.

4.  I usually________ (visit) my grandparents on weekends.  But last week I ________ (go)

    to the park.

5.  My mother sometimes________ (watch) TV in the evening.  Last night, she ________ (do)

    housework.

In this world there is no shortcut to take. So people, no matter how clever they are, can’t succeed_______ they work hard.

A．if

B．even though

C．unless

D．but

成骨肉瘤的特征有（）。

A.与大多数恶性肿瘤一样，中老年人多见

B.X线上可见Codman三角

C.由恶性成纤维细胞和成骨细胞组成

D.能形成骨样组织

E.B+C+D

据国外有人科学分析，人的正常语速是每分钟（）

A.1000个词汇

B.300个词汇

C.150个词汇

D.50个词汇

能体现人体实验科学原则的是（）。

A.以健康人或病人作为受试对象 

B.实验时使用对照和双盲法 

C.不选择弱势人群作为受试者 

D.实验中受试者得到专家的允许后可自由决定是否退出 

E.弱势人群若参加实验，需要监护人的签字