  Using the 13.7 m telescope of Purple Mountain Observatory (PMO), a survey of
J=1-0 lines of CO and its isotopes was carried out towards 98 methanol maser
sources in January 2008. Eighty-five sources have infrared counterparts within
one arcmin. In the survey, except 43 sources showing complex or multiple-peak
profiles, almost all the $^{13}$CO line profiles of the other 55 sources have
large line widths of 4.5 km s$^{-1}$ on average and are usually asymmetric.
Fifty corresponding Infrared Astronomical Satellite (IRAS) sources of these 55
sources are with $L_{bol}$ larger than $10^{3}L_{\odot}$, which can be
identified as possible high-mass young stellar sources. Statistics show that
the $^{13}$CO line widths correlate with the bolometric luminosity of the
associated IRAS sources. We also report the mapping results of two sources:
IRAS 06117+1350 and IRAS 07299-1651 here. Two cores were found in IRAS
06117+1350 and one core was detected in IRAS 07299-1651. The northwest core in
IRAS 06117+1350 and the core in IRAS 07299-1651 can be identified as precursors
of UC\simH{\sc ii} regions or high-mass protostellar objects (HMPOs). The
southeast core of IRAS 06117+1350 has no infrared counterpart, seeming to be on
younger stages than pre-UC\simH{\sc ii} phase.
