presente simple --- pasado simple
- He said: " I eat corn".He said he ate corn
presente continuo--- pasado continuo
- He said: " I am eating corn".
He said he was eating corn
presente perfecto--- pasado perfecto
- He said: " I have eaten corn".He said he had eaten corn
presente perfecto continuo--- pasado perfecto continuo
- He said: " I have been eating corn".
He said he had been eating corn
pasado simple --- pasado perfecto
- He said: " I ate corn".
He said he had eaten corn
can --- could
- He said: " I can eat corn".
He said he could eat corn
will --- would
- He said: " I will eat corn".
He said he would eat corn
must / have (got) to --- had to
may--- might - He said: " I must eat corn".
He said he had to eat corn
- He said: " I may eat corn".
He said he might eat corn