---How long do you think it will be __________ China sends a manned spaceship to the moon?--- Perhaps two or three years.
It had been half an hour before she found herself _____ in the wrong direction of her home.
His ability is beyond question; ______ has been in doubt is ______ he is prepared to work hard.
Most people would agree that nuclear science should be developed to benefit the human beings_______ harm them.
Many new means__________ to prevent the river ____________.
I like _____ in the spring when the weather is warm and everything begins to grow.