Until now, the government has only enforced the ban（ ）American s

Until now, the government has only enforced the ban（ ）American ships.
A、with regard to
B、in contrast to
C、in addition to
D、​as opposed to
【正确答案】：A
【题目解析】：本题考查介词短语辨析。with regard to：关于，对于；in contrast to：与…截然不同，与…对比鲜明；in addition to：除…之外；as opposed to：而不是。句意：到目前为止，政府仅仅对美国船只实施了禁令。故A选项符合题意。