be
supposed
to
的用法
用法一：
be
supposed
to...
其中to是
动词不定式符号，不是介词，其后要跟动词原形。当be
supposed
to...
的主语是“人”
时，意为“应该……
”；“被期望……”，它可以用来表示劝告、建议、义务、责任等，相当于
情态动词should。如：
everyone
is
supposed
to
wear
a
seat-belt
in
the
car.
每个人在汽车里都应该系
安全带。
teachers
are
supposed
to
treat
all
the
students
alike.
老师应该对所有的学生一视同仁。
用法：当be
supposed
to...
的主语是“物”时，它表示“本应；本该”，用于表示“某事本应该发生而没有发生”。如：
the
new
laws
are
supposed
to
prevent
crime.
这些新法令本应该起到防止犯罪的作用。
the
train
was
supposed
to
arrive
half
an
hour
ago.
火车本应在半小时之前到达。
用法三：
be
supposed
to后面接“have
+
过去分词”时，表示“本应该做某事而没做”。如：
you
are
supposed
to
have
handed
in
your
homework
by
now.
现在你应该已经把作业交上来了。
he
is
supposed
to
have
arrived
an
hour
ago.
他应该一小时前就到了。
用法四：
be
supposed
to...
的否定结构为be
not
supposed
to...,它常用于口语中，意为“不被许可；不应当”。如：
she
was
not
supposed
to
be
angry
about
that.
她本不该为那件事而生气的。
you
are
not
supposed
to
smoke
on
the
bus.
你不应该在公共汽车上吸烟。