Let
${\bf T}^{n}$ be the $n$-torus. We show that strengthened versions
of the $C^{r}$-closing lemma ($r\geq 1$) take place for several
classes of dynamical systems on tori; namely, 1) for Herman
actions of the group ${\bf Z}^{k}$ on ${\bf T}^{1}$; 2) for
foliations without compact leaves on ${\bf T}^{3}$; 3) for
diffeomorphisms of ${\bf T}^{1}$ with wandering chain recurrent
points; 4) for flows on ${\bf T}^{2}$ with wandering chain
recurrent trajectories and without fixed points.
We also prove a version of the $C^r$-closing lemma for
generalized interval exchange transformations on ${\bf T}^1$ under
the assumption that a nontrivially recurrent point has symbolic
expansions sufficiently
large, and as a corollary we get a version of the $C^r$ Closing
lemma under similar
assumption in terms of symbolic coding for $C^r$
vector fields with finitely many singularities of saddle type on
an orientable surface of genus$\geq 2$.