鱼与熊掌

yú yǔ xióng zhǎng

lit. the fish and the bear's paw, you can't have both at the same time (idiom, from Mencius); fig. you must choose one or the other

you can't always get everything you want; you can't have your cake and eat it

fish (CL:條|条[tiao2],尾[wei3])

and

xióng

bear

zhǎng

palm of the hand