Thanks, on my Mac (Control + Option + drag left or right) is copy。Selects the brush tool mouse right key is brush tool board.
What language are photoshop and operating system set for?
That's Chinese Simplified or Chinese Traditional?
Are you using a macbook or mac desktop with a mouse?
I'm Chinese Simplified, photoshop CC 2017 , Mac Sierra 10.12, windows Key bard and Microsoft mouse . thanks you.
Sorry, before i was responding from a macbook pro with a trackpad.
On one of our mac desktops with a windows keyboard and mouse it's
Ctrl+Alt+ Left mouse button hold and drag left or right for size
(use the actual Ctrl key, not the Windows logo key which subs for the Command key on a mac)
Of course you might have to look at your system preferences and see how the keys are set
Apple>System Preferences>Keyboard>Keyboard>Modifier Keys
very thanks, The issue has been resolved. （Ctrl+Alt+ Left mouse button hold and drag left or right for size）According to the method you said the problem solved。