in under 90 seconds是什么意思?

defeat 20zombies in 30seconds是什么意思 sixty seconds in a minute under是什么意思 seconds count in an emergency什么意思? There're ( )seconds in a minute. there are sixty seconds in a m____ It can heat the water boil in 90 seconds.请说明这里的heat与boil的用法. under the spotlight是什么意思 穿under是什么意思? under instruction是什么意思 work under pressure是什么意思 put under arrest是什么意思