The U.S.is expected to have by the end of this year, but that may increase if General Stanley McChrystal asks for additional troops, and President Obama approves it.

VOA: standard.2009.09.09

In particular, they increase the amount of norepinephrine, a neurotransmitter that's responsible for just general arousal.

具体来说,安非他命会引起,去甲肾上腺素释放量的增加,去甲肾上腺素,是种负责一般性唤醒的神经递质

耶鲁公开课 - 心理学导论课程节选

The key is we fight the same war now,". Still,even with the increased U.S.commitment, the expected increase in NATO forces and the new emphasis on developing Afghan forces, General McChrystal told his troops there is a long, difficult fight ahead.

VOA: standard.2009.12.03