Mrs Green are very grateful to the neighbour _____ helped her child out of the fire.
说老实话,做老实事,是诚实做人的基本要求。( )
小明经常长时间看漫画书而导致了近视,则他矫正视力时应配戴的近视镜是( )
设NA为阿伏加罗常数的值,下列说法正确的是( )