请详解下面这三道题
29.Istoppedtolisten,andmysonseemed_________himself_________inthelivingroom.>>
A.toenjoy,toshutB.tobeenjoying,shutting>>
C.tobeenjoying,shutD.tohaveenjoyed,havingshut>>
56.Theyarelookingforwardwithhope____A____fromyousoon.>>
A.tohearingB.ofhearingC.hearingD.tohear>>
57.Busytranslatingabook,hecouldn’thelp___A______thearticle.>>
A.writeB.writingC.wroteD.written>>
答案我都知道