零售饱和指数只能作为研I定商圈和店铺选址的参考，而不能作为惟一的标准。
参考答案：对
When and where he came here _______ yet.
A．isn’t known
B．aren’t known
C．has not known
D．have not been known
能对抗三环类抗抑郁药引起的抗胆碱能症状的有效药物是
A．毒毛旋花苷
B．西地兰
C．普鲁卡因酰胺
D．毒扁豆碱
E．利多卡因
