  We present the analysis of 16 classical T Taur stars using LAMOST and TESS
data, investigating spectral properties, photometric variations, and
mass-accretion rates. All 16 stars exhibit emissions in H$\alpha$ lines, from
which the average mass-accretion rate of $1.76\times10^{-9}~M_{\odot}yr^{-1}$
is derived. Two of the stars, DL Tau and Haro 6-13, show mass-accretion bursts
simultaneously in TESS, ASAS-SN, and/or ZTF survey. Based on these
observations, we find that the mass-accretion rates of DL Tau and Haro 6-13
reach their maximums of $2.5 \times 10^{-8}~M_{\odot}yr^{-1}$ and $2 \times
10^{-10}~M_{\odot}yr^{-1}$ during the TESS observation, respectively. We detect
thirteen flares among these stars. The flare frequency distribution shows that
the CTTSs' flare activity is not only dominated by strong flares with high
energy but much more active than those of solar-type and young low-mass stars.
By comparing the variability classes reported in the literature, we find that
the transition timescale between different classes of variability in CTTSs,
such as from Stochastic (S) to Bursting (B) or from quasi-periodic symmetric
(QPS) to quasi-periodic dipping (QPD), may range from 1.6 to 4 years. We
observe no significant correlation between inclination and mass-accretion rates
derived from the emission indicators. This suggests that inner disk properties
may be more important than that of outer disk. Finally, we find a relatively
significant positive correlation between the asymmetric metric "M" and the cold
disk inclination compared to the literature. A weak negative correlation
between the periodicity metric "Q" value and inclination has been also found.
