1·Much as water in a bathtub is not a problem until it starts to overflow, pollen for many is not an irritant until it crosses a particular threshold, he said.
浴缸里的水溢出之前不会带来大问题，大量的花粉超过一定限度后就会成为刺激物了，他说。
2·Then it gets rather more high-tech. Capua's high-vacuum, low-temperature equipment removes bergaptene, an irritant, from the oil; and it is then stored under nitrogen gas to stop it oxidising.
后来萃取的方法更加更高科技化了，卡普阿公司的高压低温设备能将刺激物，bergaptene(一种脂)与油分离；然后将香油储存在氮气中防止其氧化。
3·A colorless, pungent, crystalline compound, C18H 27no 3, that is derived from capsicum and is a strong irritant to skin and mucous membranes.
一种无色有刺激性气味的晶状化合物，C18 H 27 NO 3，得自辣椒并是对皮肤和黏性细胞膜很强的刺激物。
4·Shortly after the antioxidant or saline injections, the researchers injected formalin, an irritant, into the left hind paw of each mouse.
分别注射抗氧化剂、生理盐水后不久，研究人员又在小鼠左腿注射福尔·马林，一种刺激物。
5·Nerve impulses, hormone and organ-specific irritant can cause cell membrane depolarization.
神经冲动、激素及器官特异刺激物可以引起细胞膜去极化。