结构吊装工程所选用起重机的起重量是指其必须大于所安装构件的重量与索具重量之和。（）
参考答案：对
--- Why does the lake smell terrible?
--- Because large quantities of water _________.
A．have polluted
B．is being polluted
C．has been polluted
D．have been polluted
改良Barthel指数总分为多少分（）。
A.60
B.80
C.90
D.100
E.150
