The scientists have found it hard to clone a new healthy being.这一句的语法点或知识点是什么

the scientists have collected much____about the south pole.A advice B opinions C storiesD information Scientists have learnt a grate deal about the kinds of food people need. Scientists have discovered that sleep and dreams effect the way people feel. Scientists have ____ that motion is the source of lifea、shownb、showedc、been shownd、showing Scientists have many theorise about how the universe ____ into being Many scientists have ____(aready,yet)been to the North Pole.填什么 意思Scientists now believe that the planet could once have supported life scientists have made a lot of important d___ in science in the past ten years ---,some famous scientists have the qualities of being careful and calessAStrangely enoughBstrange enough French doctors and American scientists have reported doing an operation in which the doctor was out By 2025,scientists predict the world will have 7.8 billion people. Scientists have tried to set fire to underground coal to speed up the fires. scientists have yet to determine the date怎么翻译?主要是yet,决定还是没决定? By 2025,scientists predict the world will have 7.8billion people.变成一般疑问句! The scientists are finding the proof( )the animals have the same feelings like people.是that还是whether 英语翻译Once again,the scientists have caught us mouthing pieties while action is just the contrary.这里caught us Scientists have created the world's smalleat snowman,---about a fifth of the width of a humanhair.AmeasuringBmeasured Scientists have come up with lots of ideas to explain the end of the dinosaurs 同义句