25．They ______ the train to Beijing．Otherwise, they would have returned home．

　　　 A．need have caught 　　　　　　　　　　 B．must have caught　

　　　 C．must catch 　　　　　　　　　　　　　　　　 D．may catch

24．His father was the first on the farm ______ against the slave owner．

　　　 A．fought 　　　　　　 B．fighting 　　　　　 C．to fight 　　　　　　　　　　　　　　　 D．having fought

23．As we all know, eating too much fat can ______ heart disease and cause high blood pressure．

　　　 A．add to 　　　　　 B．attend to 　　　　 C．contribute to 　　　　　　　　　　　 D．apply to