when a shark ______ (appear),a bell rings will tell the people to get out of the water
问题描述：
when a shark ______ (appear),a bell rings will tell the people to get out of the water
答
appears.
用一般现在时.
答
when a shark appwars(appear),a bell rings will tell the people to get out of the water
当一只鲨鱼出现的时候，铃声将会响起告诉人们是时候离开水面
答
when a shark
条件状语从句主句是一般将来时,从句用一般现在时.
答
is appearing