集合资产管理计划中，委托人应了解相关权利、义务和风险，自行承担投资风险。 ( )
参考答案：对
AIDS is said _______ the biggest health challenge to both men and women in that area over the past few years.
A．that it is
B．to be
C．that it has been
D．to have been
将下列格式分解因式
（1）xy+x+y+1
（2）（x﹣1）（x+3）+4．
