There are times when writers are uncertain about what will happen and need to refer to future events as possibilities or probabilities, not as future certainties.

Here, we'll briefly review the language used to show how 'probable' future events are, i.e. what is the chance that they will happen.

We can use certain modal verbs followed by the bare infinitive (i.e. the infinitive without 'to') to refer to the future. These modal verbs can be used in the active and passive voice.

May / Might + bare infinitive

May and might are used to express the uncertain possibility of an action in the future. May expresses stronger possibility than might.

Interest rates may increase in the next few months.
Interest rates might be increased in the next few months.

Could / Can + bare Infinitive

We use can and could to express future possibility when the possibility is related to suggestions, plans or projects.

The company's lawyers think it could take a long time to draw up the contract.
We are expanding overseas, so I could be sent to China or Taiwan in the next few months.

Can expresses stronger possibility than could. However as the can of possibility is easily confused with the can of ability, may/could are usually used to avoid confusion.

They can deliver tomorrow on time. (They are able to deliver on time)
They can deliver tomorrow on time. (It is possible for them to deliver on time)

Which meaning is intended? To avoid such confusion use may.

They may/could deliver tomorrow on time. (It is possible for them to deliver on time)
They may/could attend the meeting on Friday.

Could is also used to express a conditional possibility, i.e. the possibility of something happening or not depends on something else happening.

We could go to Macau next week, if you take Monday off work.
The company could expand if it had more capital.