vi.翘起拇指请求搭乘（过路汽车），示意请求搭便车（thumb的现在分词形式）...

Thumbing的音标：...

Thumbing a lift had once a carefree, easy-going image.伸手搭便车曾经给人以轻松随意的形象。I went out onto the road to start thumbing.我走到公路上,竖起拇指要求搭车.Thumbing the book, he found a maple leaf in it.他匆匆翻了一下书, 找到一片枫叶....