adj.在肩(背)上；骑在肩(背)上
adv.在肩(背)上地；骑在肩(背)上地
n.背负式运输
vt.背；附带发生
=pickaback.
Doug gave all the children a piggyback ride. 道格让所有的孩子在他背上骑了一回马。
If only my father would give me a piggyback. 这时候真希望我爸能把我背上。
