具有智力低下的疾病是()
A.先天性甲状腺功能减低症
B.苯丙酮尿症
C.21-三体综合征
D.先天性肾上腺皮质增生症
E.粘多糖代谢障碍
参考答案:A, B, C, E
While we were running on the playground,Jack suddenly stopped ___________ and lay on the ground,so we all stopped ___________ what was wrong with him.
A.running; to see
B.running; seeing
C.to run; to see
D.to run; seeing
我们在运动场上经常看到不同肤色的运动员奋勇拼搏的情景,那么导致人种差异的主要原因是[ ]
A.自然地理环境等多种因素长期影响
B.进化阶层不同
C.体貌特征不同
D.生活习俗不同