答案選b.will be
be going to與will兩者都可表示將要發(fā)生的事、將要去做某事,但它們有如下幾點(diǎn)區(qū)別：
1.be going to 表示近期、眼下就要發(fā)生的事情,will 表示的將來(lái)時(shí)間則較遠(yuǎn)一些,如：
He is going to write a letter tonight.
He will write a book one day.
2.be going to 表示根據(jù)主觀判斷將來(lái)肯定發(fā)生的事情,will表示客觀上將來(lái)勢(shì)必發(fā)生的事情.
He is seriously ill.He is going to die.
He will be twenty years old.
3.be going to 含有“計(jì)劃,準(zhǔn)備”的意思,而 will 則沒(méi)有這個(gè)意思,如：
She is going to lend us her book.
He will be here in half an hour.
4.在有條件從句的主句中,一般不用 be going to,而多用will,如：
If any beasts comes at you,I'll stay with you and help you