两头落空 [- - luò kōnɡ]fall (to the ground) between two stools; Between two stools one falls to the ground.; If you run after two hares, you will catch neither.; If you run after two horses, you will catch none.; sit between two stools:
•¶ 如果你不及时作出决定， 就会两头落空。 If you don't make your choice in time, you are likely to fall between two stools.