问一道xdf课件上的语法题：）

5. 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（D）

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

答案是d，请问d中第一个that指什么？我理解应该指lights，但是石林讲这道题时，明确说过that前不能有逗号或者介词，除了in that. 所以我很困惑。

第一个that是指代visible equipment, such as lights 是插入语，修饰visible epuipment的。个人理解

没有这么绝对呀，要看逻辑意思的吧。

白勇语法书上说，定语从句优先就近修饰。但是具体修饰哪个要通过主谓一致或逻辑意思来判定。

你所说的这一类判断方式现在都不是绝对的，我劝你还是多注重意思的理解，多用句子完整性，并列等去判断。这些小技巧对于目前的题目都不是绝对的。