A.displaying a large red flag B.displaying three black balls in a vertical line C.sounding four or more short rapid blasts on the whistle D.continuously sounding the fog whistle
A.“四去三降一補(bǔ)”B.“三去一降一補(bǔ)”C.“三去二降—神”D.“四去一降一補(bǔ)”
A.長(zhǎng)遠(yuǎn)B.全面C.辯證D.獨(dú)特