Despite signs of a gradually improving economy, job growth continues to lag in the U.S.Unemployment remains high at 10 percent after the economy shed another U.S.Chamber of Commerce President Thomas Donohue says the reason is obvious: uncertainty is causing large and small businesses to think twice before hiring new workers.

VOA: standard.2010.01.12

There's a lag phase, there's a slow rise to an intermediate level of antibody.

会有迟滞期,在该时期,抗体浓度缓慢到达中间水平

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