We may find that learning a foreign language does not have to be________learning our mother tongue,but can in fact be twice ________.
These diagrams are especially helpful when we have a concrete problem ______ at hand.
This kind of gel pen which ______ smoothly is quite popular with students.
It is the bus driver who should ______ the safety of the passengers.
I’m very grateful to my high school teachers, without ______ help I wouldn’t be so excellent.
I ______ for Shanghai this Saturday, so I want to know when the earliest plane ______.