If I am what, if I am what, if I am what, write a poem.

If I were a big tree, I would try my best to absorb the carbon dioxide exhaled by people and spit out oxygen, so that people can have a fresh air environment. If I were a big tree, I would let my brothers and sisters get together and form a colorful forest, so that everyone can have a paradise for rest and entertainment. If I were a big tree, I would stop sandstorms and mountain torrents from harming human beings and let them live happily. If I were a big tree, I would be unlucky. I am willing to use me to build houses, furniture, plows and bridges, because I know that birds will fly around with my seeds and my descendants will continue to benefit mankind! If I were a scientist again, I would invent a multifunctional detector. It is very small and can be used by police uncles to catch criminals. After the criminal's fingerprints and physical features are known to it, we can find the criminal's whereabouts within 10 minutes and notify the local police to pay attention. We can also find evidence to prove the facts when the criminals don't plead guilty. If there is a wrong case, it is necessary to overturn it. Innocent people are not guilty, which can improve the efficiency of police uncles in handling cases. Excavators can help teachers quickly correct homework and accurately judge whether homework is right or wrong. The teacher can see the best lesson plan by tapping the name of work lightly, without having to repeat it every time. They can also find good materials for students to review before the exam and improve their ability. When practicing their compositions, we can also refer to good compositions and type good words and sentences so that we can use them in writing. If the bank network system has such equipment, the effect will be better. When hackers invade, explorers can fight alone without manual operation, and the means are extremely clear and victorious. It can also identify the authenticity of coins, even if it is realistic, it can't escape its eyes. If it defends peace in the United Nations, it can negotiate peace with the countries at war in situ and defuse the smoke of war with a high success rate. I want to be a useful talent for my motherland!