beg for，表示乞求，恳求，例如：
1.We are not going to beg for help any more.我们不会再乞求帮助。
2.We need help but we will not beg for it.我们需要帮助，但不会乞求帮助。
3.He wants to see them beg for mercy.他想亲眼看着他们求饶。
4.Alone again, he knocked on the doors of Polish farmers to beg for help.再次落单之后，他敲开波兰农户的门乞讨、求助。