英语强调句请说明选哪一个,为什么.特别是后两题which和that 到底选哪个?（1） It is from the e

英语强调句
请说明选哪一个,为什么.特别是后两题which和that 到底选哪个?
（1） It is from the earlier time _______ men began to study the natural phenomena and the heavenly bodies.
A.what B.and C.when D.that
（2） The mural art of painter Charles Alson that had established his reputation and insured his fame.
A.The B.That the C.It is the D.Since the
（3） It is the high humidity ________ makes London winters so chilly,not the low temperature.
A.which B.that C.what D.this
（4） It was the training that he had when he was young ______ made him such a good engineer.
A.that B.which C.what D.who