图为“非洲大陆荒漠化示意图”。读图,非洲荒漠化严重区主要出现在( )
A:热带雨林带
B:热带草原带
C:热带荒漠带
D:亚热带常绿硬叶林带
0.3÷0.25=____
0.4÷0.16=____
He _______ an English club last year and has improved his English a lot.