Scientific work is differentiated from art by its necessary connection with the idea of progress.
科学工作不同于艺术在于它与进步的概念有必然联系。
I dont believe its necessary to buy the bigger one.
我认为没有必要买容量大一点的。
So its necessary to evaluate the role of infection in more studies.
这两种观点都有其依据，因此尚需进一步研究评价感染因素的作用。
So its necessary to introduce and generalize the situational teaching.
因此，在哲学教学中，引进和推广情境式教学是十分必要的。
Its necessary to plan for the future.
对未来进行规划是有必要的。
Its necessary that we should have a walk now.
我们有必要出去散散步。
Its necessary that we should have a walk now.
我们有必要出去散散步。
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