Question

Great as Newton was, many of his ideas _______ today and are being modified by the work of scientists of our time.

A．a(chǎn)re to challenge	B．may be challenged
C．have been challenged	D．a(chǎn)re challenging

Answer 1

C

考查時態(tài)。句意“盡管牛頓很偉大，但是他的很多想法在當今已經(jīng)受到挑戰(zhàn)了，正在被當代的科學家進行修改�！卑l(fā)生在過去的事情，對現(xiàn)在造成的影響，用現(xiàn)在完成時。主語是復數(shù)，故謂語用原形have。Ideas和challenge是動賓關(guān)系，用被動語態(tài)。故選C。