This also keeps the air，soil，water crops________ chemicals.
| A．out of | B．out from | C．free of | D．rid of |
It was with these feelings _______ I began the creation of a human being.
| A．that | B．when | C．which | D．where |
Most animals and plants are sensitive _______ sudden changes in temperature.
| A．for | B．with | C．to | D．in |
Water, _______ seems so simple and common, is what makes life possible.
| A．that | B．as | C．what | D．which |
You _______ not drive so fast. There is plenty of time.
| A．need | B．could | C．may | D．can |
I will never forget how happy I was when I _______ China again.
A. set feet in B. set foot in C. put foot in D put feet in