牡丹种子种植方法:had to/will

had to/will HAD BEEN TO had /have to后是不是加动词原形啊? 区别be going to do/will do/will be doing/be to do want to=will? Describe a situation where you have had to adopt/ initiate new approaches The man had to __ his living. She had learnt to suffer without complaining. THEY HAD TO CROSS A VIVER How long will it take to go to Beijing by train/plane?