he teacher told them since light ________ (travel) faster than sound,lightning ________ (appear) to go before thunder.
travels, appears
暂无解析
________(catch)intherain,hewaswettotheskin.
Themorewelookedatthepicture,________.
________(fail)severaltimes,theyneedsomeencouragement.
Somemoleculesarelargeenough________(see)undertheelectronicmicroscope.
Thefloordoesnotlooksobadwhen________(sweep)clean.
