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走近高考

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Noun clauses as the subject主语从句 1.　　　　　 it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.  2.　　　　　 many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas.  3.So 　　　　　life will continue on the earth for millions of years to come will depend on whether this problem can be solved. 

What　

What　

whether