爱不释手: to love sth too much to part with it (idiom); to fondle admiringly...
轮流: to alternate, to take turns...
丁: ding ［fourth of the ten Heavenly Stems（天干）］, fourth...
汗水: sweat, perspiration...
交替: to replace, alternately, in turn...
穿越: to pass through, to traverse, to cross...
