什么是“开元杂报”？
The Acme company has determined that during its busiest hours， the average number of internal VoIP calls across the WAN link is four （4）. Since this is an average， the WAN link has been sized for six （6） calls with no call admission control. What will happen when a seventh call is attempted across the WAN link？ （） ["the seventh call is routed via the PSTN","the call is denied and the original six （6） calls remain","the call is completed and the first call is dropped","the call is completed， but all calls have quality issues","the call is completed but the seventh call has quality issue"]
有落水危险的船只必须设（）。 ["救生圈；","安全带；","扶手；","监护哨。"]
请解释幼儿园环境的概念，并举例说明。
《平家物语》写于？（） ["平安时代","室町时代","镰仓时代","江户时代"]
目前已知的主动转运系统：
