【单选题】It is not feasible to build sea defense to protect against erosion because it is too costly and will endanger neighboring areas.
【简答题】How does the guest upstairs feel when she knows what is going on?
【判断题】Alexandrite is costly by its color change.
【判断题】网络分发服务:通过互联网获取各种能力,并可以通过按需随意的方式访问,以通过各种客户端接入使用。