@WBYeats,
Quote:-I have done what I could to add my small weight in an attempt to tip the balance on the side of hope, but it has been my puny effort against vast forces.
This is from a book, but the context can't tell me whether COULD refers to past or present, so let's assume there's no context. In English, in 'I have done what I could', what, present or past things, does COULD refer to?
This is a past event in that the speaker seems to consider their efforts finished. That doesn`t mean that the speaker can`t-couldn`t continue, if the person changed their mind.
Tense is indicated by
have done. COULD is a tenseless verb which can be paraphrased as,
I have done what it is possible for me to do to add my small weight ... .
CAN can-could also be used here;
I have done what I
can to add my small weight ... .
CAN is a tenseless verb which can be paraphrased as,
I have done what it is possible for me to do to add my small weight ... .