第一题：truly 这是副词,修饰动词told
第二题：第一个填 to help 不定式做目的状语 、 第二个填 find 这是help sb do sth的用法,帮助某人做某事
第三题：seriously .副词修饰动词told
My friends_(true) told me about it.
We can do our best_(help) the lost boy_(find) his mother.
Mr Wang told us_(serious)we got lost.
说一下语法点和翻译!