伤脑筋: to be a real headache, to find sth a real headache, to beat one's brains...
作对: to set oneself against, to oppose, to make a pair...
不难: not difficult...
交情: friendship, friendly relations...
找: to try to find, to look for, to call on sb, to find, to seek, to return, to give change...
古: ancient, old, paleo-...
