他总是带着一丝忧郁的表情。

He always has a touch of melancholy in his expression.

他有着忧郁的表情。

He has a melancholy look.

水滴鱼实际上全身都是一张脸，这种苍白、胶状的深海生物长有大大的嘴唇，忧郁的表情似乎马上就要融化在地板上。

The blobfish is practically all face -- a pale, gelatinous deep-sea creature whose large-lipped, sad-sack expression seems to be melting toward the floor.