What are you looking for？
I'm looking for the book __you lent me yesterday．（ ）
A．whoB．thatC．whoseD．what
The river is too wide for the swimmers _______________.
| A．to swim | B．to swim in |
| C．to swim across | D．swimming |
I am happy with my old friends today.
| A．play | B．to play | C．playing | D．plays |
The policeman asked us _____him send the old man to the hospital.
| A．help | B．helps |
| C．helping | D．to help |
（）If there _____ no buying and selling of animals, there will be no killing in nature.
| A．is | B．will be |
| C．has | D．will have |
In summer milk will quickly go bad_____ it is put into a fridge.
| A．though | B．unless | C．because | D．once |