At least four high-flying warplanes had to take evasive action.是什么意思？

At least four high-flying warplanes had to take evasive action.

至少有4架高空飞行战斗机不得不采取避让行动。

at

prep. （表示位置）在，在（某时间或时刻），以，达， 向，朝；n. 阿特（老挝辅币单位，100 阿特 = 1 基普）；

例句
Prices start at £13.95 a metre for printed cotton...
印花棉布以每米13.95英镑的价格起售。

least

pron. 最小的，最少的，程度最轻的；adv. 最少，最小；

例句
Balsamic vinegar is aged in wood for at least 10 years and the flavour is wonderful...
意大利香醋在木桶中就经历了至少10年的酝酿期，所以口味极佳。

four

num. 四，四个，第四；n. 四个人（或事物）的一组，得四分的一击，四人赛艇；

例句
His car was held up and he was abducted by four gunmen...
他的车遭遇拦劫，随后他被4名持枪歹徒劫持。

warplanes

n. 军用机( warplane的名词复数 )；

例句
They're backed by allied warplanes and tanks.
他们受到盟军战机和坦克的掩护。

had

v. 有（ have的过去式和过去分词 ），（亲属关系中）接受，拿，买到；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

take

vt. 拿，取，采取，接受（礼物等），耗费（时间等）；vi. 拿，获得；n. 镜头，看法，收入额，场景；

例句
I take care of them to the best of my abilities...
我尽我所能地照顾他们。

evasive

adj. 逃避的，推托的，闪烁其词的，含糊的，

例句
He was evasive about the circumstances of his first meeting with Stanley Dean...
他避而不谈他和斯坦利·迪安第一次会面的情况。

action

n. 行动，活动，功能，作用，手段，[法]诉

例句
The government is taking emergency action to deal with a housing crisis...
政府正采取紧急措施解决住房危机。