智力障碍包括：（）、（）
参考答案：精神发育迟滞、痴呆
—What time will Mr Brown be back to China?
—Sorry. I don’t know ______.
A．when did he go abroad
B．why he is going abroad
C．how soon will he be back
D．how long he is going to be there
2，7， 19， 31， ( )
A．8
B．21
C．34
D．46
