find，find out，look for与discover find，find out，look for与discover都与“找”有关，但侧重点不同。请观察下面的例句。【例句】1. Im looking for my pen.2. He cant find his watch.3. I find it difficult to learn English well.4. Please find out the answer to the question.5. Do you find out why Tom was late?6. Scientists around the world are working to discover a cure for AIDS.【用法】look for意为“寻找”，强调找的动作，是延续性动词，如句1。find意为“找到、发现、感到”，强调找的结果，是非延续性动词，如句2和句3。find out意为“查明、发现、了解”，指经过认真观察、调查或研究把某事、某物查出来、搞清楚，多用于复杂而不容易直接查出的情况，如句4和句5。discover意为“发现、发觉”，指发现某种情况或发现早已存在而未为人知的东西，如句6。【运用】请根据所给汉语意思，完成下列英语句子，每空词数不限。1. 最后，我在床底下找到了那本书。I _ under the bed in the end.2. 我爸爸正到处找他的护照。My father _ his passport everywhere.3. 我们必须查明真相。We must _. 4. 你知道哥伦布什么时候发现了美洲吗？Do you know when Columbus _ America?Key:1. found that book 2. is looking for 3. find out the truth 4. discovered