讲解：
look forward to sth./doing sth. 
固定搭配；表示“期待；盼望”
He was looking forward to working with the new Prime Minister.
他期待着与新首相共事。


So am I. 
固定用法；表示“我也是”，指前面所讲的情况也适合于另一个人
She's worried about you. Quite frankly. So am I.
她很担心你，老实说我也是。


force sb. to do sth. 
动词搭配；表示“强迫某人做某事”：
I was forced to sign the agreement against my will.
我被迫违心地在协议上签了字。


up to sb. 
固定用法；表示“由……决定”
It's up to you to decide whether to go or to stay.
是去是留该由你决定。