防備的英文：
to guard against

guard是什么意思：
n. 卫兵；护卫队；守卫；警戒；防护装置；列车长
v. 看守；监视；控制；防范

guarding position
防守位置

a guarded answer
谨慎的回答

...the Irish Guards
...爱尔兰近卫团

a security guard
安全警卫

The sentry is on guard.
那哨兵在站岗。

against是什么意思：
prep. 与...相反；对...不利；倚靠；以防；以...为背景；和...相比

It is against federal law to discriminate against blacks.
歧视黑人是违反联邦法律的。

She was drugged against the pain.
她服麻醉药止痛。

He informed against the drugpusher.
他告发了那个毒品贩。

Rain pattered against the window.
雨点吧嗒吧嗒拍打着窗户。

Array the army against the enemy.
列阵对敌。