填写一级航行通告限定行时，影响半径有几位数?单位是什么?
A、三位数字，海里A
暂无解析
________, John has been to several foreign countries.
________ so many people in the United States been out of work as today.
________ the concert had begun did we realize what a splendid show it was going to be.
The poor countries are extremely _______to international economic fluctuations
某车间计划 10 天完成一项任务，工作 3 天后事故停工 2 天，若仍要按原计划完成任务，则工作效率要提高 ( ).
