Inglese per la moda - could

Modal verbs and their usage

Can and be able to

Can has no infinitive form, no -ing form, no perfect form, and no future form. It cannot follow another modal auxiliary verb. On all of these occasions, we have to use be able to instead. Compare the following:

• I'd like to be able to swim like Jack. He swims like a fish.
• When I'm at the sea-side, I enjoy being able to take a swim every morning.
• Unfortunately, Jack hasn't been able to swim since his accident. Let's hope he'll be able to resume his daily swimming training soon.
• I'm not a member, but can I swim in this pool? ~ Why don't you speak to the secretary? She may/might/should be able to help you.

Could

Could can be used in many different ways:

• To ask for permission
• To make a request
• To express ability when referring to the past

Examples:

• By the time she was seven, she could already speak three languages.
• Could I take a look at your collection?
• Her brother Jack was an excellent swimmer. He could beat anybody in his class.

Was able to / managed to

We tend to use was able to or managed to if we are talking about what happened in a particular situation or are referring to a specific achievement:

• It was very icy, but I managed to keep the car on the road.
• Veronica was very upset when Ben left her, but she managed to smile nevertheless.
• She didn't really want to go to Mexico, but Tony managed to persuade her somehow.

Examples:

• Were you able to / Did you manage to speak to him before he left home? ~ No, I'm sorry, I wasn't able to / didn't manage to reach him.
• The fog came down, and I wasn't able to / didn't manage to get to the top of the mountain.
• My brother wanted to carry on, but we managed to / were able to talk him out of it.

Use of could with senses and thought processes

However, with verbs that refer to the five senses (see, hear, smell, feel, taste) and with verbs that refer to thought processes (understand, believe, remember, decide), we normally use could, even when we are talking about specific occasions:

• He was standing very close to me, and I could smell the garlic on his breath.
• He asked me when Julie's birthday was, but I couldn't remember.
• I couldn't decide whether to ask him for a lift or not.
• I could see that he'd been running.

Unable to / not succeed in

Unable to is an alternative negative form of not able to, and succeed in is a slightly more formal alternative to manage to. But remember that succeed in is followed by verb + ing, rather than verb + infinitive: