Yǒujūn de dào lái jídà de zēngqiáng le fángyù lìliàng.
The arrival of allied forces greatly strengthened the defensive capability.
Tips
usage
友军误伤 (yǒujūn wùshāng) means 'friendly fire' — accidentally harming one's own allies. The term is also used figuratively for people on the same side who inadvertently harm each other.