`->` Mr. Tuan told her that he could help her the following day.

`-` Câu tường thuật (Câu kể)

`+` S + said (to sb)/told sb + (that) + S + V(lùi thì)

`-` Lùi thì: can + V-inf `->` could + V-inf

`-` I `->` he

`-` you `->` her

`-` tomorrow `->` the following day / the next day

`------------`

$\color{yellow}{\lll \text{NhatHuy}
\color{orange}{\text{ThichChoiLiqi} \ggg}}$