下列各句中，没有语病的一句是（ ）

As a teacher , you patient .

They _________ laughing when they heard his funny voice.

you come to a party on Saturday, Peter— Oh, ______I’m already going out, I’m afraid.

Why not paint the Golden Gate Bridge blue or other colors—The bridge has always been painted “International Orange” ______ that color is easier to see in the heavy fog.