tablet computers like Apple’s iPad just before bed, a research says recently, can lead to poor night’s sleep.
Since 1949, the peoples living standard _______, causing a big _______ in population.
______ has already been pointed out, grammar is not a set of dead rules.
There is a mountain ________ the top is always covered with snow.
---Why did the police _____ the crowd? ---Because the presidents car ____ in the street.
John, as well as the other children who _____ no parents, ________ good care of in the school.