I wonder _____ Mr Black changedhis mind to take part in the movement — After he listened to the speech by MrKing

It is fashionable to drive a car, but to drive a car is not nearly as difficult as it is imagined on condition that you ________ the specialized rules.

________ our teacher is ill, ________ he still come to our class to teach us.

When _____, the wholesale vegetable market will be the largest one in China[ ]

_____ his father came back from work_____his homework.