填空。
15-8=____,12-8=____,17-8=____,16-8=____
13-7=____,11-7=____,12-7=____,16-7=____
下列代数式书写规范的是( )
8hm2=____m2
1900hm2=____km2
(注:1hm2 =1公顷)
1928年,格里菲思的肺炎双球菌的转化实验,成功的表明了( )
从方框中选择恰当的词或短语并用其正确的形式填空(每个词或短语只能用一次)。
busy; difficult; dream of; be covered live ; arrive in; be away;
row a boat; in one's fifties; out of control ; have a chat with