June 10 (Reuters) - Canada's main stock index started

the week on a muted note as gains in materials and energy stocks

from higher commodity prices were offset by investor caution

ahead of crucial U.S. inflation data and the Federal Reserve's

monetary policy meeting later in the week.

At 9:30 a.m. ET (13:30 GMT), the Toronto Stock Exchange's

S&P/TSX composite index was down 9.92 points, or

0.05%, at 21,997.08.