________ twice a year, whether it is a car or a bus or a truck, is the rule that every driver must obey in this city.
Don't try to get off the bus ____ it has stopped.
To understand the grammar of the sentence,you must break it______ into parts.
He will tell you about it ____ you get there.
The classroom is big enough , but we’ll have to move if we have more students.
We shall go ____ you are ready.