An act of Congress requires a cut-off of most U.S.aid to countries where elected governments are unseated by the military.

VOA: standard.2009.07.01

So z equals 7 -- this is the cut-off where, in fact, the sigma orbital is going to be higher in energy than the pi 2 p orbitals.

所以z等于7-这是分界点，实际上，sigma轨道能量,要比π2p轨道高。

麻省理工公开课 - 化学原理课程节选

z And what you need to remember is if the z 8 is equal to eight or greater, such as oxygen being the cut-off point, this sigma 2 p orbital is actually lower in energy than the pi 2 p orbitals, the molecular orbitals.

你们要记住如果,等于或者大于，就像O是分界点，这时sigma2p轨道,比π2p轨道能量更低。

麻省理工公开课 - 化学原理课程节选

Hassan Moinuddin of the Asian Development Bank's Mekong Sub-Region Program says a warmer climate could cut almost seven percent off the region's gross domestic product by the end of this century, by reducing crops or forcing the relocation of communities.

VOA: standard.2009.12.21