There was a slight, but _____ air of disdain. A: imperceptible B: imperceptibly C: perceptible D: perceptibly

(Each) employee with (a modicum of intelligence) (would be able to) undertake (such) a basic process. A: on the verge B: incurring C: while D: imperceptibly

随着社会的不断发展我们的一些关于爱情和婚姻的观念正在不知不觉地发生变化。(imperceptibly)