Exercise 1 -43:
Yes, You Can or No, You Can't?
Next you use a combination of intonation and pronunciation to make the difference between can and can't.
Reduce the positive can to [k 'n] and stress the verb.
Make the negative can't ([k渀(t)]) sound very short and stress both can't and the verb.
This will contrast with the positive, emphasized can,
which is doubled—
and the verb is not stressed.
If you have trouble with can't before a word that starts with a vowel, such as open,
put in a very small [(d)]—
The keys k渀(d) open the locks.