单项选择题
Who was Jack（）
A. The family’s bulldog. B. Laura’s little brother. C. The little boy next door.
单项选择题 The first credit card was issued just before World War Ⅰ.（）
单项选择题 The first real "card" issued by Diners Club in 1950 could be used in many various places.（）
单项选择题 What are the two factors that contribute to longer life expectancies for people（）
