---How old ________ you?---I ______ ten years old.

Maybe you have been to many countries, but nowhere else ________ such a beautiful place. 

Three fourths of the ________ in the country have run out.

– A number of students ____ in the dinning hall.-- Let me count. The number of the students ____ about 400.

Listening attentively in class and reviewing in time _______ a sure way to improve your learning, and this is especially true _______ it comes to standard tests.