  The correlations between the shape of rapidity distribution of the yield of
light charged particles and the fragmentation modes in semi-peripheral
collisions for $^{70}$Zn+$^{70}$Zn, $^{64}$Zn+$^{64}$Zn and $^{64}$Ni+$^{64}$Ni
at the beam energy of 35MeV/nucleon are investigated based on ImQMD05 code. Our
studies show there is an interplay between the binary, ternary and
multi-fragmentation break-up modes. The binary and ternary break-up modes more
prefer to emit light charged particles at middle rapidity and give larger
values of $R_{yield}^{mid}$ compared with the multi-fragmentation break-up mode
does. The reduced rapidity distribution for the normalized yields of p, d, t,
$^3$He, $^4$He and $^6$He and the corresponding values of $R_{yield}^{mid}$ can
be used to estimate the probability of multi-fragmentation break-up modes. By
comparing to experimental data, our results illustrate that $\ge$40\% of the
collisions events belong to the multi-fragmentation break-up mode for the
reactions we studied.
