I come to Beijing for the first time.(同义句转换) This is the first time that I _____ to Beijing. He will come back _in_two_days_.(对划线部分提问) _____ will he come back? He has been in the army for 15 years.(同义句转换) It has been 15 years since he ______. What is Jack doing in the afternoon?(用do his homework进行回答) Jack___________ in the afternoon. He often does his homework before school.(变为一般疑问句) ________ his homework before school?