一道英语阅读题阅读理解 Mrs Green asked her young son to look after his

一道英语阅读题
阅读理解
Mrs Green asked her young son to look after his baby sister for half an hour while she was doing housework.
The boy took the baby out into the garden and they were playing happily.Suddenly the baby began to cry."Billy,What's the matter with Susan?Why is she crying?" Mrs Green shouted to her son when she heard the baby's cry.
"She wants my coins (硬币)." answered Billy.
"Well,let her play with a few of them if it will stop her crying." said Mrs Green.
"But she wants to keep them!" answered Billy.
"No,she doesn't!" Mrs Green said."She's only a baby.She is too young to understand anything!"
"But I know that she wants to keep the coins," answered Billy."She has already swallowed (吞下) two of them!"
2.Susan started to cry because ___________.
A.she swallowed two coins
B.she wanted more coins
C.she wanted to keep the coins
D.Billy took away her coins
但我还是想不通
那也可能是那个小婴儿还想要更多的硬币啊，吞硬币应该没有什么感觉吧，小孩而已