You can always fall back on him when you are in difficulties.你碰到困难时总是可以求助于他.Doctors sometimes fall back on old cures.有时医生们求助于老的疗法.When necessary, instinct is the most reliable resource you can fall back on.必要时，最保险的办法就是凭直...

fall back on的音标：fall back on的英式发音音标为：[fɔ:l bæk ɔn]fall back on的美式发音音标为：[fɔl bæk ɑn]...

求助于，依赖，转而依靠...