1 there is no need

2 why should

1 certainly

2 must

3 will

4 necessarily

1 necessary

2 essential

3 indispensable

4 required

1 to have to

2 must

3 compulsory

4 necessarily

1 general

2 military leader

3 fierce man

1 lit. if three walk together, one can be my teacher (idiom, from the Analects of Confucius)

2 you have sth to learn from everyone

1 forgetting the fate of Ding and Dong (idiom)

2 unheeding the lessons of the past

1 lit. when two tigers fight, one is sure to be wounded (idiom)

2 fig. if it comes to a fight, someone will get hurt

1 He who gives no thought to far-flung problems soon finds suffering nearby (idiom, from Analects).

2 Smug concentration on the here and now will lead to future sorrow.

1 if two tigers fight, one will get injured (idiom)

2 if you start a war, someone is bound to get hurt