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(单选题)19.（ ） (单选题)18.（ ） (单选题)17.（ ） (单选题)16.（ ） (单选题)If more people give up driving cars, the air will get much _ (单选题)—Is that Miss Liu over there?—No. It ______ be her. She has (单选题)—Our hometown is becoming more and more beautiful.—Sure. Man (单选题)—How long ______ your brother ______ this camera?—For two we (单选题)—I have two soccer balls, what about you?—Oh, I don’t have _ (单选题)—Excuse me, can I sit here?—______. The old man who sat here