2. Researchers have still to decide whether smell is one sense or two—one responding to odours properly and the other registering odourless chemicals in the air. 研究者们还需要判断嗅觉到底是一种还是两种感觉,一种感觉回应气味本身,另一种感觉记录空气中无味的化学成分。
3. Pure air is colourless and odourless. 纯空气是无色无臭的。
4. The hunt for the odourless pig. the hunt for the odourless pig猎寻无气味的猪barnyard externalities。