类风湿关节炎好发年龄是（）
A.15～20岁
B.20～45岁
C.25～50岁
D.30～55岁
E.35～60岁
参考答案：B
Tom _____ a piece of waste paper, and put it into the rubbish bag. [ ]
A. put away
B. threw away
C. stood up
D. picked up
A．→+
B．+→+
C．+→++10
D．→+
→
+
+
+
+
+10
