Actually, you should consider this advice. You want to use strong verbs in your writing. The verb “to be,” when used as a linking or copulative verb, merely connects or couples the subject with the predicate. It’s a weak verb. For example:
• Becky is an expert computer programmer.
• Your dog was well behaved.
• They were zombies.
While these are fine sentences, you might not want to use too many of them in a row. They merely describe things. There’s no action.
So far so good. But what about these sentences?
• Becky is working as an expert computer programmer.
• Your dog has been behaving well this morning.
• They were being eaten by zombies.
None of these sentences uses “to be” as a linking verb. Here, a form of “to be” is acting as a helping or auxiliary verb. Do not avoid using “to be” in these kinds of sentences.
In English, verbs have few forms, but we have many shades of meaning that we want to invoke. To do that, we use a variety of auxiliary verbs to show time, questions, negation, completion, repetition, willingness, possibility, or obligation. If you’re a native speaker, you can do all this without thinking about it – but you might not precisely understand how you’re using the language. You can easily fall prey to mistaken ideas if you don’t know grammar.
In the sentence, “Becky is working as an expert computer programmer,” the main verb is “to work.” The “is” in the sentence makes the verb tense present progressive, also called present continuous. It can be used in a variety of ways. In this case, it shows an ongoing action, what Becky is doing over a period of time.
“Your dog has been behaving well this morning” similarly shows your dog’s ongoing action, but during a specified period of time expressed by the present perfect continuous tense. It says that your dog was behaving well in the past and is continuing to behave well in the present, or at least until right now. English grammar allows us to make complex statements about when things happen.
Notice that both of the above sentences are active voice.
“They were being eaten by zombies” is passive voice and past progressive tense. The eating is being carried out on the subject of the sentence, “they,” and that’s what makes it passive: the subject receives the action. I have an inordinately long rant (a ten-part workshop, in fact) about identifying and properly using passive voice here, so right now I’ll just say that the main verb is “to eat,” and both “were” and “being” are helping verbs, not linking verbs.
So here’s my point: if you see a form of the verb “to be,” this might not indicate a copulative use. If you want to strengthen your writing, look a little deeper before you make any rash decisions. Don’t just circle every form of “to be” as a way to decide whether there are too many of them. There might be just the right amount if you’re trying to say something complex.
— Sue Burke