"he was my best friend at the university"
"he's a good ally in fight"
"I have trouble remembering the names of all my acquaintances"
"we are friends of the family"
"all their supporters came out for the game"
"they are friends of the library"
befriend vt. 以朋友的方式对待;帮助;照顾;
boyfriend n. 男朋友;情郎;
friendly adj. 友好的，亲密的;有帮助的;互助的; adv. 友好地，朋友般地;
girlfriend n. 女朋友;女性朋友;