I worked on the problem ____ a long time and I worked it out ____ myself ____ last.[ ]

Icanhardlyheartheradio.Wouldyouplease?

Practising Chinese kung fu can not only ________ one’s strength, but also develop one’s character.

If you want to be ___________, please keep ____________ every day.

Is your iPad black, Mary?–No, it isn’t. ______________ is white.