be indispensable to do还是doing

be found+doing还是to do? be addicted to do还是doing? be worth to do 还是doing 英语be going to do还是doing be advised doing还是 to do be successful in +doing 还是 to do? be bound to do 还是doing be surprised + to do还是doing be difificult for sb do 还是doing还是to do be indispensable for 与 be indispensable to 的区别 be willing to do还是be willing to doing be equal to do还是be equal to doing