The more one is ______ the English-speaking environment, the better he or she will learn the language.

A．kept up

B．filled in

C．caught in

D．exposed to

正常成年女性红细胞计数值不低于

A．2.5×10¹²/L

B．3.0×10¹²/L

C．3.5×10¹²/L

D．4.0×10¹²/L

E．5.0×10¹²/L