After the bell rings, which indicates the ending of the exam, you_____ stay ____ you are until all your papers are collected.
We were swimming in the lake _____ suddenly the storm started.
---Have you read the timetable ? ---Yes . The train ____ at 10:12 p.m..
Do you know __________ ?
The message is very important, so it is supposed _______ as soon as possible.
Visiting _______ Great Wall is ________ unforgettable experience to me.