题目内容：
Once the logic of a network is laid out, the project manager will conduct a forward pass and then a backward pass through the network．Doing this will provide information on the and the lead to the identification of the ．（ ）
A．Slack for each activity, critical path
B．Slack for each activity, high-risk activities
C．Manpower shortages, high risk activities
D．High risk activities, non-critical paths A．每项活动的时差，关键路线
B．每项活动的时差，高风险活动
C．人力短缺，高风险活动
D．高风险活动，非关键路线
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答案解析：