声音在海水中的速度为1500 m/s,从海洋勘测船上竖直向下发出超声波,经3.2 s后收到海底反射回来的超声波,则海底有多深?(声音在海水中匀速传播)
2400
--If you like the new house, I suggest you buying it.
---But it's really too expensive. I can't______ it.
A.get
B.afford
C.supply
D.support
下列有关“蜡封法”的叙述中,错误的有()。
A.本试验方法适用于易破裂土和形态不规则的坚硬土
B.用削土刀切取体积大于30cm3试件,应注意保留试件表面浮土及尖锐棱角并称量,准确至0.01g
C.将石蜡加热至刚过熔点,用细线系住试件浸入石蜡中,使试件表面覆盖一薄层严密的石蜡
D.若试件蜡膜上有气泡,需用热针刺破气泡,再用石蜡填充针孔,涂平孔口