A. 新想法在被接受之前要經(jīng)過多次檢驗(yàn),這是常識(shí).
before是介詞,后面要用動(dòng)名詞結(jié)構(gòu)的.這里還有個(gè)被動(dòng)的關(guān)系在里面.因此不用A而選擇B.
作連詞的話B選項(xiàng)應(yīng)該是they're fully accepted (by people)
語法上可以把before以及before后面的全部去掉,但是句意有點(diǎn)不完整了.我的意思是，before 后面 It is a common sense that new ideas have to be tested many times before (they were) fully accepted 的they were 能不能直接省略，不是加being ？我感覺口語上應(yīng)該可以，其實(shí)回答之前我也糾結(jié)了一會(huì)兒。不過既然這里出了這一道題，而又有A選項(xiàng)在這里，從做題的角度看，選A好一點(diǎn)。………………………………………………………………