Passive Voice with Necessity

If you have studied the Passive Voice before, you will remember that it is used when the object receiving the action is more important than the agent performing the action. The object and the subject change places in the sentence like this:

Active:
We upgraded the system yesterday.

Passive:
The system was upgraded yesterday.

This is a classic example of a passive sentence. The object changes position to become the new subject and is followed by the verb BE and the past participle, in this case was upgraded.

But what if we want to do something different? What are the alternatives?

One option is to use NEED.

The library needed compiling in a certain way.

This sounds like an active sentence, but it has a passive meaning. We use the verb NEED followed by a gerund in an active construction to create a passive meaning. Just like in the classic BE + past participle passive voice construction, we are focused on the person or the thing that receives the action. 

If we’re going to avoid race conditions, the threads need processing in a consistent sequence.

Just like the previous example, this is an active construction forming a passive meaning. NEED is followed by the gerund processing. 

The threads need processing is the same as the threads need to be processed, but the first one sounds more direct, as if the necessity is more urgent. This is because of the active construction. We can imagine somebody saying this in the moment, when the necessity occurs. 

The second one sounds more formal, as if it is a written, general instruction.

So, the NEED + GERUND construction can be used as a very effective way of creating passive meaning whilst expressing necessity. It needs practising