Lighter than air, but harder to breathe

轻于空气，但难以呼吸

But her voice was too even, and the air was harder to breathe.

可她的声音太平坦了，我几乎透不过气来。

Carrying extrapounds also makes it harder to breathe -- a problem you don't want whenyou're suffering from allergies.

身体负荷多余的脂肪会造成你呼吸困难，当你遭受过敏症状的时候，呼吸困难也是你不想碰到的。