+176.+ _Can_ is the present-time form and _could_ the past-time form,
and both imply ability or power to do or to be. _You can go_ means _You
are able to go_,--_You have the power to go_. _You may go_ means _You
have permission to go_. _Can_ is often used when we should use _may_,
when we mean to give permission. Habit plays a great part in our life
and knowledge of the right way does not always suffice. It is only
continued effort that will establish correct habits of speech. Good
English would be easy of accomplishment if "to do were as easy as to
know what it were good to do."
We are too often like the mother in the story. "Can I have a piece of
pie?" asked the child. "May I?" the mother corrected. Then the child
asked, "May I have a piece of pie?" and the mother answered, "Yes, you
can." Knowledge said, _may_; habit said _can_, and the ready tongue
obeyed the force of habit.
Say the correct word over and over aloud until it sounds right to your
ear and flows readily to your tongue.
+177.+ _Could_ is sometimes used in the present sense to denote power to
do, conditioned upon willingness, as:
He could if he would.