Her popularity has been on the wane for some time.

她的人气一段时间以来江河日下。

《牛津词典》

As time went on, their hopes began to wane.

随着时间的消逝，他们的希望开始变得渺茫。

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The levels of immune response tend to wane with time, he said.

对病毒的免疫能力随着时间减弱，他说。

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Like the British Empire, however, the seafaring group is bound to wax and wane over time.

FORBES: Magazine Article

In every year, there is a similar trend, with half of the famous people getting that way by relatively young age, seeing their fame (measured by the number of times they are mentioned in books) increase rather dramatically, and then seeing that celebrity wane as time passes and they age and die.

FORBES: Wanna Be Famous? Science Says Get There By Age 30

Some old ideas that emerged around the same time as supersymmetry are being resurrected now there is a prospect that supersymmetry may be on the wane.

BBC: LHC results put supersymmetry theory 'on the spot'