To be subject to something means to be affected by it or to be likely to be affected by it.
Prices may be subject to alteration…
价格可能会有所变动。
In addition, interest on Treasury issues isn’t subject to state and local income taxes.
另外，国债利息不需缴纳政府和地方所得税。
//…a disorder in which the person’s mood is subject to wild swings from mania to depression.
患者情绪在狂热和抑郁之间疯狂起伏的紊乱状态