单选题：— Do you have a minute? I've got something to tell you. —..

_____ he opened the window, a sparrow flew in.A. Though B. The moment C. If D. Unless

—Peter told me he wanted to come with us. Is it OK for you?— I don't mind _____ he pays for his meals.A. as far as B. as well asC. as long asD. as soon as

— Do you think he will finish the job on time? — Sure. _____ he _____ to do it in his own way.A. As soon as; will be left B. Even if; leaves C. Whenever; has left D. So long as; is left

—I heard they went skiing in the mountains last winter. —It true because there was little snow there.A．may be notB．won’t beC．couldn’t beD．mustn’t be

____ most of the earth's surface is covered by water, fresh water is very rare and precious.A. As B. Once C. If D. Although