It is necessary to explain your theory _____, otherwise theaudience won't make sense of what yo

题目简介

It is necessary to explain your theory _____, otherwise the audience won't make sense of what you are trying to get across.

A．on purpose

B．at length

C．at random

D． on average

题型：单选题难度：偏易来源：不详

试题分析：句意：有必要详细地解释你的理论，否则观众就不会明白你想要表达的意思。A. on purpose故意地；B. at length详细地；C. at random随意；D. on average平均。故选B。
考点: 考查介词短语的用法。