use·able /ˈjuzəbəl/
  (a.)可用的;使用方便的;有用的
  useable
       adj 1: fit or ready for use or service; "the toaster was still
              functional even after being dropped"; "the lawnmower
              is a bit rusty but still usable"; "an operational
              aircraft"; "the dishwasher is now in working order"
              [syn: functional, usable, in working order(p), operable,
               operational]
       2: able to be put to use; "usable byproducts" [syn: usable]
       3: convenient for use or disposal; "the house is available
          after July 1"; "2000 square feet of usable office space"
          [syn: available, usable]