equivalent vs. equivalency
辨析：前者是后者的形容词形式，分别是“等价的”和“等价性”。注意前者也可以作为名词表示“等价物”。
例句：
The first two messages in Figure 2 and Figure 3 perform equivalent actions.
On the Chinese equivalent of YouTube, "OMG" has garnered more than seven million views.
There is a tendency by some Western commentators and journalists to forward moral equivalency in the name of balance.