It all depends或That depends表示“這很難說”“得看情況”。
depend的用法4：在口語中,作為開場白或結束語的depend upon〔on〕 it意思是“無須懷疑”“我敢說”,可以看成是省略了you may
depend的常用短語：
depend on〔upon〕 (v.+prep.)
1、依賴,依靠 rely on; count on; get help or support from; get money or food and clothing from
depend on〔upon〕 sb/sth
depend on〔upon〕 sb/sth for sth
depend on〔upon〕 sb to-v
2、相信; 信賴 have no doubt; be quite sure; trust; be sure of
depend on〔upon〕 sb/sth/v-ing
depend on〔upon〕 sb to-v
3、隨…而定 be influenced or determined by,(no pass) vary according to
depend on〔upon〕 sth/wh-clause
depend的用法例句：
1. Remember, happiness doesn't depend upon who you are or what you have; it depends solely upon what you think.--Dale Carnegie
請記住，幸福不在于你是誰或者你擁有什么，而僅僅取決于你的心態!
2. Whether such properties are a good deal will depend on individual situations.
這樣的地產是否可獲得大筆收益還要視具體情形而定。
3. They depend on the goodwill of visitors to pick up rubbish.
他們相信游客會自覺撿起垃圾。
4. The Oxfam shops depend on regular supplies of saleable items.
樂施商店靠出售一些人們定期捐贈的適銷物品維持經營。
5. Self-discipline, willingness, enthusiasm, that's what you must depend on.
自律、自愿與熱情，這是你所必須依仗的。