单项选择题A．abstractB．conversationC．introductionD．passage
单项选择题A．challengingB．boringC．dullD．simple
单项选择题A．recursB．occursC．incursD．arises
单项选择题A．carefulB．carelessC．care-freeD．cared
单项选择题A．boringB．shortC．meaninglessD．simple
