fluctuate around

In fact, each stock has its value, stock prices should fluctuate around the value.

其实, 每个股票都有其价值, 股价应该是围绕着价值而波动.

After the rotor passes its resonant zone, the phase angle does not increase any more, and it begins to fluctuate around a constant value ( 2n+ 1)π rad.

在远离临界转速的高速区，转子的相位角不再增大，而是围绕某一定值波动，此定值为（2n+1）πrad（n为自然数）；

mr smithers prefers the idea that markets are "imperfectly efficient" , in other words, that they fluctuate around their fair value.

Smithers先生认为市场的“有效是不完美的，”换句话说，其价值围绕公允价值上下波动。