decide
 

Am I correct?

-John __ to improve his French since then.
-Japan __ granted this status since 1989.

My opinion: decided and was are wrong; and has decided and has been should be used, because of since.(At least according to what I learned from Susan)

But something does not feel right: the act of granting should be non-continuous, so I think even 'has been granted' is wrong, but in that case, another doubt is cast on 'has decided': the act of deciding seems also non-continuous, so 'has decided' seems also wrong. In that case, I'm not even sure what verbs I have to use.

Re: decide
 

Your reasoning is correct - the present perfect is necessary with since because the event must be seen as lasting from past to present. But, as you say, it would be more logical to see the act of "granting" the status as a past event, and say either :

Japan was granted this status in 1989.
or:
Japan has had this status since 1989.

Re: decide
 

Excellent answer. Thank you. But since you only commented on 'grant', not 'decide', do you agree with me that 'decided' in the above is wrong and 'has decided' is the correct choice?

Re: decide
 

Possible yes, but it would need a convincing context to show that I didn't know when the specific decision moment (which is an event with a specific time) was :

Matteo made a complete fool of himself when he gave that speech. But I know that he's decided to improve his English since then.

This implies that he's already made the decision - but not necessarily that he's put it into action. For that you'd need to say eg :
After that disastrous speech, Matteo decided to take English lessons. And he's improved a lot since then.


So as always it depends on the context, how he speaker perceives the event and what exactly they want to express. If you leave those out of your examples it's very difficult to give a definite answer.

Re: decide
 

Excellent answer. Thank you.

Re: decide
 

Do you mean 'decided', the simple past, is possible even when since is used to indicate the time? If yes, could you think of an example? I couldn't, because the simple past with decide is used to talk about a non-continuous act, which means that if decided, not have/has decided, is used, it must be talking about a particular moment, not something that since can refer to.

Re: decide
 

Not in the same clause, no. Look at the examples above. The verb in the clause with since is always in perfect aspect.

What I'm saying is that it would be unusual to use the verb decide together with since, as, generally, you know when the decision was made. I've given a couple of examples when it might be possible to say eg since then, indicating that I don't know exactly when the decision was taken (or if he's actually done anything about it. But generally a decision happens at a specific moment - which you know about - and it's what you decided to do that happens afterwards, as in the last example.

As always, you must consider the context. language use doesn't happen in a vacuum. It's affected by the situation. The problem with your examples is that the context is never provided. If you give one, then you'll find it's much easier to understand why certain forms are used rather than others. That's why my answers always add one.

Re: decide
 

Excellent answer. Thank you.