81.Keep in () that all people are different and some may progress faster than others.

31.The engineers in this lab spent several weeks () their plans for the new bicycle.

30.He () to study harder in the future so that he could have more opportunities to find a better job.

29.He tried to ()relations with his former wife but he failed.

28.The pressure () causes Americans to be energetic, but it also puts them under a constant emotional strains.

27.Had he worked hard, he () the exams.

26.The soldier was () of running away when the enemy attacked.

25.According to Papousek, the pleasure babies get in achieving something is a reflection of ().

24.The babies would “smile and bubble” at the lights because ().

23.In Papousek’s experiment babies make learned movements of the head in order to ().

22.Papousek noticed in his studies that a baby ().