we use reported speech to convey what someone has said, there is
often a tense change. It might be said that the verb form in what
is reported moves one tense back. Thus, when it comes to modal verbs:
will & can change to would & could may & shall change to might & should
'Can I borrow your jumper?' - 'He asked me if he could
borrow my jumper.'
'I'll pick you up from the station.' - 'He said he would
pick us up, but he's not here!'
'I may be back late tonight.' - 'He admitted he might
be back late.'
'What shall we give her as a gift?' - 'They wondered what
they should/could give her.'
that there is no further change to past modal auxiliaries would,
could, might or should when these forms appear
in direct speech format:
'Would you help me to find her?' - 'He wondered if I
would help him to find her.'
'We might look for her in Leeds.' - 'He suggested they
might look for her in Leeds.'
ought to, used to, needn't
modal auxiliary verbs, however, do not change in reported speech.
Ought to is already a past tense modal (cf. should)
and used to exists only in the past tense. Needn't is
a strange auxiliary verb as it exists only in the negative. It is
possible to change must to had to in reported speech, although this
is usually not done. Compare the following:
'We must leave right now.' - 'They insisted they must/had
to leave straightaway.'
'You needn't come with us.' - 'They told me I needn't
go with them.'
'You ought to go and stay with mum.' - 'They thought
I ought to go and stay with mum.'
'You must try not to worry.' - 'They told me I must
try not to worry.'
need is used as a main verb (cf want), it behaves
as any other main verb when direct speech is reported:
'Do you need any bread from the shop?' - 'He asked me
if I needed any bread.'
'He's fired. I don't need to see him.' - 'He told me
I was fired and he didn't need to see me.'
'He needs my help and I must go to him.' - 'She said
he needed her help and she must go to him.