He asked me whether my brother ________ (fly) to Beijing.
had flown
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heteachertoldthemsincelight________(travel)fasterthansound,lightning________(appear)togobeforethunder.
________(catch)intherain,hewaswettotheskin.
Tosucceedinascientificresearchproject________.
________(fail)severaltimes,theyneedsomeencouragement.
Ipreferthisdiagram________thatone.
