OG11（紫）-34

1.        Lacking information about energy use, people tend to overestimate the amount of energy used by equipment, such as lights, that are visible and must be turned on and off and underestimate that used by unobtrusive equipment, such as water heaters.

(A) equipment, such as lights, that are visible and must be turned on and off and underestimate that

(B) equipment, such as lights, that are visible and must be turned on and off and underestimate it when

(C) equipment, such as lights, that is visible and must be turned on and off and underestimate it when

(D) visible equipment, such as lights, that must be turned on and off and underestimate that

(E) visible equipment, such as lights, that must be turned on and off and underestimate it when

答案是D，没有疑问。但是OG指出AB的错误之一是定语从句that 后用了are，与equipment不一致。但是that are visible 在AB中不是应该用来修饰lights吗所以用复数形式吗？

哈，理解了~