①____ A.read B.play C.book ②____ A.Friday B.Wednesday C.birthday
③____ A.sports B.Monday C.Friday
④____ A.weekend B.science C.music
⑤____ A.maths B.often C.Chinese
俗话说“食不言,寝不语”,吃饭时不能大声说笑的科学道理是( )
8.4÷x=7
x=____