________(fail)severaltimes,theyneedsomeencouragement.
heteachertoldthemsincelight________(travel)fasterthansound,lightning________(appear)togobeforethunder.
Heaskedmewhethermybrother________(fly)toBeijing.
Iknowitisn’timportantbutIcan’thelp________aboutit.
Ishallneverforget________(meet)thelatePremierZhouduringhisinspectionofourfactory.