81.  According to a research, within a talk, boys always sit at angles to each other and look elsewhere in the room , seeming to be casual and pay little attention.

82.  Why could online education be so popular within such a short amount of time?

83.  A more rigorous research indicates that the way people behave can be different within neighboring areas.

84.  We see that the nature of a nation can be delicately controlled by the location of their habitation, just within Europe.

85.  Firstly, for young people they should arrange their time properly, and learn to use it within proper time.

86.  Besides, we should control the length of time when we surf the internet within an acceptable period.

87.  That information has to be very recent (like within the past hour) for it to be useful to you.

88.  Every time I think of him, I could feel the warmth from within.

89.  We share our secrets buried deep within ourselves, exchange our views, she can give me some advice in a timely manner.

90.  Furthermore, when biology and chemistry met, biochemistry came into being, which is the effort to understand biology within the context of chemistry.