He was frustrated by his inability to wave down a taxi.连一辆出租车都打不到，他很沮丧。When things go wrong, all of us naturally feel disappointed and frustrated.出问题时，我们大家自然都感到失望和沮丧。He often appeared angry and frustrated by the intransi...
植物的肺就是其叶片上微细的气孔。A plant's lungs are the microscopic pores in its leaves.在干旱的条件下, 叶子的膨压减少而气孔关闭.Under conditions of water stress, leaf turgor decreases and stomata close.他使橡胶塞牢固地塞进盖上的排气孔.He presses the rubber stopper ...