415 + 715 =____
56 ﹣ 16 =____
25 + 25 =____
34 ﹣ 14 =____
12 + 12 =____
13 + 14 =____
15 ﹣ 18 =____
2﹣ 34 =____
1﹣ 18 ﹣ 38 =____
I ______ the League for 5 years so far.
根据所学知识回答问题:
下列有关心脏、血管及血液的说法正确的是( )