A common memory they all have ______ their school days is the school uniform.
--- And then the ________ wind blew the roof off. --- Oh, you must have been ________.
Could people become infected ____ HIV by swimming in a pool or sitting in a bath?
There are too many difficulties for us _______ . We really don’t know _______ to do.
Who do you think is the greatest man _______?
________ is mentioned(提及) above, the number of the students in senior high schools is increasing.