留一手[liú yì shǒu]
词典hold back a trick or two：留一手；留了一手。
留一手[liú yì shǒu]
hold back a trick or two (in teaching a trade or skill)
1. 凡做事留一手，凡用钱不花罄，听人言不全信，对人语有保留
Do not all you can; spend not all you have; believe not all you hear; and tell not all you know.
2. 他总要留一手的。
He hasn't finished with you yet.
3. 我认为，我们应该可以从他们里抽调更多的驻扎在南朝鲜，留一手。
I think we should park some more of those troops in South Korea just in case.
4. 我留一手，暂时不把这一想法说出来。
I'm keeping this idea up my sleeve for the time being.
5. 避免使用这些工具的方法就是在打击恐怖主义时留一手。
To eschew such tools is to fight terrorism with one hand tied behind your back.
6. 哇，你还真是有留一手的锦囊妙计呢。
Wow, you surely have a card up your sleeve!
7. 哇，你还真是有留一手的锦囊妙计呢。我想，我们除了祝福中兴百货这次能度过难关，这也是我们目前能做的最好安排了。
Ian: Wow, you surely have a card up your sleeve! While we hope Sunrise can get through this crisis, this is the best we can do for now.