For the first time the W.H.O.raised its alert level from phase four to phase five on April twenty-ninth.

VOA: special.2009.05.06

C H 3 So any time you see c h 3 here, remember that that's methyl and that's going to be a terminal group.

因此一旦你看到，记得这就是甲基,而且只能在结构的末端。

麻省理工公开课 - 化学原理课程节选

For example, if t* is the time you hit the ground, then t* satisfies the equation h - 1/2 g ^2 = 0.

例如,如果在 t* 时刻落地,那 t* 就满足等式 h - 1/2 g ? ^2 = 0

耶鲁公开课 - 基础物理课程节选

He said it represents the first time an investigational H.I.V.

VOA: special.2009.10.13

Any time you see a c h 3, this means a methyl group.

一旦你看到一个，C，H，3，的组合，这就意味着一个甲基。

麻省理工公开课 - 化学原理课程节选

Last time I began with Alexander H. Stephens's famous Cornerstone Speech in 1861, the famous passage by the Vice-President of the Confederacy declaring slavery the cornerstone of the Confederate Movement.

上次我说到亚历山大·H·史蒂芬,1861年著名的奠基石演讲,就是那个邦联副总统做的讲话,声称奴隶制是邦联运动的奠基石

耶鲁公开课 - 美国内战与重建课程节选