?2x?1??2x?3??4，
13当??x?时等号成立不等式m?1?f?x??x?1?2x?3有解，
22∴m?1???f?x??x?1?2x?3??min，
∴m?1?4，∴m?1??4或m?1?4，即m??3或m?5， ∴实数m的取值范围是m??3或．
①+er(r) , jumper farmer Runnerspeaker diver winner traveler driver, robber teacher writer worker waiter (waitress) painter, cleanerseller player surfer singer owner ②+or Visitor park——parking mean——meaning Beginning inventor conductor inspector（检查员） pack——packing（包装） hiking Shopping Actor (actress ) surf——surfing breathing ④describe---description enter---entrance please---pleasure develop ---development 二、动词变为形容词 Close ---closed interest——interested frighten ——frightened break ——broken sleep ——asleep wonder——wonderful 三、名词变为形容词 care——careful Pain ——painful heath——healthy cloud——cloudy shower——showery fog——foggy south——southern wool——woolen person ——personal America ——American Italy ——Italian Britain ——British invent ---invention know---knowledge sit ---seat decide——decision discuss--discussion live---life fly ---flight disappear ---disappearance die---death rob ---robbery excited ——excited surprise ——surprised fry ——fried enjoy ——enjoyable wake——awake thank——thankful frustrate ——frustrated (挫败的) die——dead worry ——worried lose ——lost forget ——forgetful color——colorful use——useful luck——lucky rain ——rainy snow——snowy sun ——sunny north——northern confidence ——confident post ——postal Australia ——Australian china ——Chinese England ——English help——helpful success——successful noise——noisy mist——misty wind——windy danger——dangerous friend——friendly Canada ——Canadian Japan —— Japanese France ——French
Germany ——German 四、形容词变为名词 good——goodness true——truth proud ----Pride 五、形容词变为副词 ①+ly useful, wide, strong ②改y为,再加ly 六．形容词和副词同形。 unlucky discover impossible careless unknown disappear homeless busy——business dry ——drought important ---improtance different ——difference confident ——confidence （信心） healthy , heavy, happy, lucky, noisy, unlike unhappy unusual unfriendly cross——across pass——past science ——scientist library——librarian friend ——friendship
