题目内容：
Whataretheinventorsdoinginthelab?
A．Replacingcarbonfiberswithshril B．Testingahrilk'suseinwetcondition
C．Makingshrilkoutofusedhouseholdgood
D．Improvingshrilk'sflexibilityformedicalpurpose
参考答案：
答案解析：