Amazingly, these mitochondria were once free - living bacteria that were captured by an early single - celled eukaryote.令人惊奇的是, 这些线粒体曾是被早期 单细胞 真核生物俘获的自生细菌....
卢克曾经很想能及格，他大概现在还是很想。Luke badly wanted a pass mark. Still does, I daresay.及格分为A到E几等。Passes are graded from "A" down to "E".这是及格和不及格的差别.It'sthe difference between a pass and a fail....
推进器的叶片已经安装好了.The propeller blade has been mounted.然后地面控制人员将会发射推进器，把卫星送入正常轨道。Ground controllers will then fire the booster, sending the satellite into its proper orbit.较轻的推进器采用液态氢, 较重的采用自燃推进剂.The lighter version used liqu...