思考与探究 I.单项选择。 (A )1.The worst feeling isour fans A.letting,down B.let,down C.let,off D.letting,off 导航页导航页 思考与探究 Ⅰ.单项选择。 ( )1.The worst feeling is _________our fans_________. A. letting, down B. let, down C. let, off D. letting, off A