up a tree是比喻陷入困難的處境。
up a tree字面上是形容動物被攻擊時為逃避追趕而爬上樹，但他的敵人在樹下虎視眈眈地等待，因此這個動物已經無路可走。
例：They found the drugs in his suitcase, so he was up a tree. (他們在他的手提箱裡起出毒品，他因此百口莫辯。)
例：This whole business has me up a tree. (這整個事件讓我陷入困境。)
參考：
http://idioms.yourdictionary.com/up-a-tree
http://idioms.thefreedictionary.com/up+a+tree
at the end of one's rope 山窮水盡，束手無策
VOA美國習慣用語
hit a bad patch 遇到困難，陷入困境
a bad patch 是指一段不好過的時間，習慣上前面加上 hit
也可以用 a rough patch、a rocky patch，意思一樣。
Their marriage has hit a bad patch.
他們的婚姻有問題了。
http://www.english.tw/space-11101-do-thread-id-1479.html
hit a snag
= 遇到挑戰/困難; 出問題
We hit a snag with our travel plans. 我們旅遊的計畫生變。
Our plans for a relaxing night at home hit a snag when a pipe burst in the basement. 我們在家享受一個放鬆的夜晚的計畫並不順利，因為地下室的水管爆裂。
https://idioms.thefreedictionary.com/hit+a+snag
in a pinch 在緊急或困難的時候
I was in a pinch because I had no money to pay for the meal.
因為沒錢付飯錢，我那時真的很窘。
in a jam = in a difficult situation.
I'm in a jam. I'm going on holiday to Spain tomorrow but I can't find my passport anywhere. 我現在的狀況很不妙。我明天就要去西班牙渡假了，卻找不到我的護照。
I found myself in a jam when my car overheated on the highway. 當我的車在公路上過熱時，我發現情況不對勁了。
If at any time he's in a jam she'll be by his side. 只要他陷入困境，她就會在身邊陪伴他。
in a bind
Their refusal to sign the contract has put us in a bind.
他們拒絕在合同上簽字, 這使我們處於困境。
in a pickle 處境困難，沒有解決的辦法
I'm in a pickle between my employees and my boss. I won't be able to please both parties.
我夾在我的員工與老板之間，處境困難。我沒辦法讓兩邊都滿意。
