My brother can _____ a horse.

All _____ is a continuous supply of the necessities of life.

Please call Jenny ________ 536-4428. [ ]

Hello, this is Jack. May I speak to Tom?– Sorry, he isn’t in at the moment. If he _______ back, I’ll ask him to call you back.

On April 12, 1961，_____27—year—old Yuri Gagarin(尤里.加加林)became the first human to go into_____ space.