The policeman always _____ his post and struggled against the difficulties to protect the safety of the people and their property.

Was ________ problem solved?—We were trying to think of ________ way out, but it was difficult to find one.

Hurry, there is a bus coming.—Why run? There’ll be another _______.

The young man spent as much time as he ______ over his lessons

you have been to many countries, butnowhere else _____ such a beautiful palace.