{{B}}quEstions 15-18{{/B}}

A、A、tEmporAry ConDition whErE you Don’t FEEl Any progrEss in lEArning.
B、A、FlAt AnD smooth spot in your stuDy whErE you mAkE FEwEr mistAkEs.
C、A、long-tErm strugglE whiCh DoEs not Bring you Any tAngiBlE rEwArDs.
D、An EDuCAtionAl rEsEArCh on lAnguAgE lEArning thAt is unusuAl AnD ADvAnCED、