the cost of direct u.s.military operations什么意思

operation,见《牛津高阶英汉双解词典》第2个意项：activity,often involving several people and /or spread over a period of time,即,行动.
the cost of direct U.S. military operations：直接用以美国军事行动的费用.
The cost of direct U.S. military operations in Iraq already exceeds the cost of the 12-year war in Vietnam.
美国直接用以在伊拉克军事行动的费用已经超出了历时12年的越南战争的开销.