The armed forces were on high alert to guard against any retaliation.武装部队处于高度戒备状态, 以防发生任何报复活动。

You can guard against possible allergies by choosing products formulated for sensitive skin.您可以选择敏感肌肤配方产品, 以防止发生过敏。

This year's results have been excellent, but we must guard against complacency.今年的成绩一直很好, 但是我们必须要戒骄戒躁。