peoples - people,只有作为人种的意思时才用复数
boy - boys,该用复数
distant - distance,用名词表示距离；后面的at不如用between更恰当些,表示最近点之间的距离
because - because of,后面跟的是名词
usual - usually,在动词前应用副词
swim - swimming,跟在介词in后面用动名词
a - an,后面是元音开头的Englishman
Since - From或去掉on,since then = from then on,从那时候起
across - crossed,用动词cross的过去时态,across是介词,这里也可以在across前加动词swam
sea前加the,特指English Channel
corer - coat,涂抹,常与with连用,表示将……涂抹在……