细胞的这种向里推进标志着原肠胚形成的开始.This pushing - in of cells marks the start of gastrulation.外胚层囊胚的外层,在原肠胚形成之后生后外胚层组织.The outer layer of a blastula that gives rise to the ectoderm after gastrulation....
Some good might come of all this gloomy business.生意不景气也未必全是坏事。The short-term outlook for employment remains gloomy.近期的就业前景依然暗淡。Inside it's gloomy after all that sunshine.尽管阳光明媚，里面依然暗淡无光。...