题目

在音乐会上，不同的乐器演奏同一首乐曲，同学们也能够分辨出不同乐器发出的声音。这主要是依据 A.音色             B.音调          C.响度             D.频率 答案：A I have ________ French. What about you?A.many difficulties to learnB.a few troubles in learningC.quite a little difficulty to learnD.a great deal of trouble learning