In ____late 19th century, computers changed _____great deal and were widely used______international trade.
— It’s too late. Let’s leave it tomorrow. — ________! We can start it earlier next morning.
—Mummy, could you buy me a skirt like this? —Certainly. We can buy ________ one than this, but ________ this.
There is ________ in population that a food shortage is caused.
________ with the other students, the girl has better listening and speaking ability.
He always helps us ________ he is doing when we turn to him for help.