Onlywhenyouhaveobtainedsufficientdata________cometoasoundconclusion.

________(fail)severaltimes,theyneedsomeencouragement.

Ishallneverforget________(meet)thelatePremierZhouduringhisinspectionofourfactory.

Night________(fall),wehurriedhome.

Thedirectorrecommendedthatshe________(study)moreEnglishbeforegoingabroad.