用have / has + been doing 构成现在完成进行时
A: How long have you been skating?
B: I've been skating since nine o'clock.
A: How long have you been collecting cans?
B: I've been doing that for two years.
collect, skate, pair, since, raise, several, stamp, kite, anyone, store, cake, coin, been, capital, European, Russian, Australian, thousand, foreigner, quite, certain, miss
skater, shell, monster, globe, collector, common, extra, topic, writer, the Olympic Games, particularly
marathon, Jewish, Jew
run out of, by the way, be interested in, more than, far away