trong những vật sau đây vật nào phản xạ âm tốt nhất a. ko khí b. mềm, gối c. rèm cửa d. cửa kính

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The children can read English,..........................? He's ten years old , ...........................? Ba came on a bicycle , ............................? The Smiths have got a car , ..................................? Your grandfather was a millionaire , .................................? Tom should try again , ...............................? It could be done , ........................? Your brother 's here, ................................? That's Tim over there , ....................................? This will fit in your pocket,..............................? His wife has headaches quite often , ..............................? She 's got lovely blue eyes ,...............................? Prices keep going up ,..............................? I've seen you before ,.............................? Bill's written a novell ,...............................? His mother 's very proud of him ,............................? The twins used to play rubby , ...........................? Tom might be at home now ,..........................? We must hurry ,.............................? You'd been there before , ...............................? I'd like a drink,...............................? Mary ought to cooked it for them , .................................? That was Ann on the phone ,.............................? The Smiths need two cars , ..............................? He used to eat raw fish ,..........................? You'll help me ,.................................? There'll be plenty for Bill,...............................? You 'd better wait for Bill ,............................? You'd come if I needed help,................................? You'd come at short notice ,............................?