用方框内所给单词的适当形式填空（5分）

用方框内所给单词的适当形式填空（5分）

小题1:The traffic accident caused a fire __________, no one was killed.
小题2:It’s important to get at least eight ____________ of sleep every day.
小题3:Yesterday is my brother’s _______________ birthday.
小题4:Smoking is the second ___________ cause of death in the world.
小题5:There are about two ____________ students in our school.[