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。
