即可作為可數名詞也可作為不可數名詞
1、作為希望或愿望時，既可數也不可數
1 [uncountable and countable] what you think or hope will happenexpectation that For some time he lived with the expectation that he was going to die.
in (the) expectation of something Anne left Germany in the expectation of seeing her family again before very long.
against/contrary to (all) expectations Against all expectations, getting up at five is actually easier in winter.
Having raised expectations (=made people more hopeful), he went on to help only a few people.
above/below expectations Profits are below expectations.
beyond (somebody's) expectations Gina has succeeded beyond our expectations.
The show exceeded all expectations (=was much better than expected).
come/live up to (somebody's) expectations His performance did not live up to our expectations
(=was not as good as we expected)
The number of people who attended fell short of expectations (=was lower than expected).
2、作為一種對某種東西的一種期望時，可數，通常使用復數形式
2 [countable usually plural] a feeling or belief about the way something should be or how someone should behaveexpectation of Women who have high expectations of marriage are often disappointed.
Some people have totally unrealistic expectations of both medical and nursing staff.