Could have and Should have

Could have vs. Should have

Offer options and advice after an event has occurred

Options and Advice of Past Events

After a disaster, such as the sinking of the Titanic, people analyze options

that were available at the time.  Then they recommend changes so that

accidents can be avoided in the future.

Could have and Should have

COULD HAVE SHOULD HAVE

Could have expresses an opinion or suggestion for a past  option  not  chosen. Other  hypothetical  choices are discussed after a tragedy  in order to avoid a re-occurrence.

Should have expresses  an  opinion  or  advice  for  a past  situation.  After  other  hypothetical options are considered,  the  best option(s) is/are  selected as advice.

A PAST OPTION LATE ADVICE

Passengers could have taken other smaller transatlantic ships.

he owners should have supplied enough lifeboats for everyone.

The captain could have chosen a more southern transatlantic route.

The captain should have insisted on better emergency preparation.

The owners could have pressed designers to include more safety flotation compartments.

The passengers should have asked about the number of lifeboats.

Watchmen could have asked the captain to slow down due to fog.

The captain should have been cruising more slowly in the northern ship lanes.

Could have is used for alternative options.  There are many things that could have been done.  Maybe, they would have made a difference, maybe not.

Should have is used for the best option. This is / these are the key, most important, things that would have made a difference.  (After the Titanic Inquiry, they became recommendations for changes in maritime rules.)

Could Have

Lost Opportunity

Could have — had the opportunity, but didn't take it

OPTION HYPOTHETICAL STATEMENT

1)  Offer more life jackets. he owners could have supplied more life jackets. (but they didn't)

2)  Hold emergency practices. The captain could have held emergency practices. (but he didn't)

3) Keep in contact with other ships in the area. The captain could have radioed other ships in the area to ask about iceberg sightings. (but he didn't)

One expression with two meanings

TATEMENT OF POSSIBILITY HYPOTHETICAL STATEMENT

The captain could have refused help.  Maybe he did, maybe he didn't.

The captain could have refused to pilot the ship.but he didn't.

The Titanic could have been off course, too far north. Maybe it was, maybe it wasn't.

The captain could have held emergency practices.but he didn't.

The captain of the ship Californian could have ignored the call. Maybe he did, maybe he didn't.

The White Star Line could have supplied more boats.but they didn't.

Should Have

Late Advice

Should have — advice given after-the-fact

ADVICEHYPOTHETICAL CAUSE - EFFECT STATEMENTS

1) Include more life boats and better deployment  (lowering them)

The owners should have had enough space in the lifeboats for everyone on board. 

  The crew should have known how to lower the boats even if the ship was tipping over.

2) Require faster emergency response from other ships in the area.

The captains of the Californian and Carpathia should have had their radios on. 

  They should have responded to distress flares that were shot in the sky.

3) Be more watchful in shipping lanes where icebergs exist.

The captain should have listened to earlier reports of icebergs in the area.

SHOULD HAVE AND COULD HAVE

Should (not)Have + Past Participle

Could (not)

Important to Remember

Something else

• We could use could (or might or may) + have + past participle to speculate about the past. 

• We use it  to say that a past event was possible but didn’t happen.

• We use should + have + past participle to express past regrets ( I should have worked harder) or to criticize past actions. (You should have worked harder)

Third Conditional

We use it for no possibility

If I had won the lottery, I would have bought a car.

e.g.

Third conditional talks about the past, about a condition in the past that

did not happen. That is why there is no possibility for this condition. The third

conditional is also like a dream, but with no possibility of the dream coming

true.

According to the previous statement we can say that

So the condition was not true, and that particular condition can never be true because it is

finished. We use the Past Perfect tense to talk about the impossible past condition. We

use would have + past participle to talk about the impossible past result. The important

thing about the third conditional is that both the condition and result are

impossible now.

More Examples

A little more

Something important to remember

THIRD CONDITIONAL

If + past perfect, WouldCould (not)might

Have + past participle