If the government clamps down on the protestors, that will only serve to strengthen them in the long run. [VERB PREP. + on]

如果政府镇压抗议者，从长远来看，这将只能使他们更加坚决。

Banking regulators failed to clamp down until earlier this month. [VERB PREP.]

银行监管机构直到本月初才开始严格管制。