OG详解-OG6 文法 Q5

Choice D is the best answer. The convention being tested is subject-verb agreement. The plural verb “reveal” agrees in number with the plural subject “objects.”
Choice A is incorrect because the singular verb “was revealing” doesn’t agree in number with the plural subject “objects.” Choice B is incorrect because the singular verb “has revealed” doesn’t agree in number with the plural subject “objects.” Choice C is incorrect because the singular verb “reveals” doesn’t agree in number with the plural subject “objects."