什么是专升本，就是字面上的专科升本科学历吗？

义务教育是我国依法统一实施，所有适龄儿童少年必须接受的教育，具有（ ）。

A.自觉性、免费性与普及性
B.免费性、统一性与选择性
C.强制性、免费性与普及性
D.福利性、自觉性与普及性

促甲状腺激素释放激素（　　）

A.蛋白质激素

B.肽类激素

C.胺类激素

D.类固醇激素

E.固醇类激素

从13名学生中选出两人、副组长，不同的选举结果共有（）

A.26种
B.78种
C.156种
D.169种

The first true piece of sports equipment that man invented was the ball.
In ancient Egypt,as everywhere,pitching stones was a favorite children's game．But a badly thrown rock could hurt a child．Looking for something less dangerous to throw,the Egyptians made what were probably the first balls.
At first,balls were made of grass or leaves held together by vines．Later they were made of piece of animal skin sewed together and stuffed with feathers or hay.
Even though the Egyptians were warlike,they found time for peaceful games．Before long they had developed a number of ball games,each with its own set of rules．Perhaps they played ball more for instruction than for fun．Ball playing was thought of mainly as a way to teach young men the speed and skill they would need for war.

The ball was probably invented because__．

A.throwing stones often caused injuries
B.throwing stones was not fun
C.games with stones did not have rules
D.rocks were too heavy to throw