It all depends或That depends表示“这很难说”“得看情况”。
depend的用法4：在口语中,作为开场白或结束语的.depend upon〔on〕 it意思是“无须怀疑”“我敢说”,可以看成是省略了you may
depend的常用短语：
depend on〔upon〕 (v.+prep.)
1、依赖,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; 信赖 have no doubt; be quite sure; trust; be sure of
depend on〔upon〕 sb/sth/v-ing
depend on〔upon〕 sb to-v
3、随…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
请记住，幸福不在于你是谁或者你拥有什么，而仅仅取决于你的心态!
2. Whether such properties are a good deal will depend on individual situations.
这样的地产是否可获得大笔收益还要视具体情形而定。
3. They depend on the goodwill of visitors to pick up rubbish.
他们相信游客会自觉捡起垃圾。
4. The Oxfam shops depend on regular supplies of saleable items.
乐施商店靠出售一些人们定期捐赠的适销物品维持经营。
5. Self-discipline, willingness, enthusiasm, that's what you must depend on.
自律、自愿与热情，这是你所必须依仗的。