A.50kPa B.100kPa C.140kPa D.170kPa
A.30km/h B.35km/h C.40km/h D.45km/h
A.二短一長(zhǎng)聲 B.二長(zhǎng)一短聲 C.一短一長(zhǎng)聲 D.倆短聲