Write down the main idea of each part. Parts Paragraphs Main Ideas Part Three Paras. 6 – 9 It is very important to make observations of _________________. However, owing to lack of __________, compared to__________ exploration, ocean exploration is lagging far behind, with the result that we know as yet little about the deep sea. Part Four Paras. 10 – 12 True there are _________________to be made and lots of work to be done, but it is worth our while to do so as we might find______________ on Earth.