I happened ____ this book before.A.having read B.to have read C.read D.reading

I happened ____(meeting) an old friend in the supermarket this morning. An important event that I remember well was __ ___________________.It happened in/on ____ _________ at /in __________________.When I heard the news of this event/ When this event happened,I was ____________.My friends were _________________.This eve I do not know why this happened! I happened ____ this book before.A.having read B.to have read C.read D.reading When you called me this morning ,I happened to havewhy? The meeting happened right before I set this up. This happened more than once to friends I know When you called me this morning ,I happened to have （2）13.I heard a dog _____ in the next house.Did you know what ____?A.barking；happened B.barking;happen C.bank;happened D.to bark;happened14.I ____ up at 5 a.m this morning,so I an very sleepy now.--Take good care of ____.A.wake;you B.woke;y ( )2.An accident ____ on this road last week.为什么不能选B而选D?( )2.An accident ____ on this road last week.A.has been happened B.was happened C.is happened D.happened This is ____( I )brother. this is what happened I happened ____(see) the accident when i was walking past the park. I'm ____(terrible) sorry for this. i want a ____ like this i ____(glad) ___share this room___you I'm ____in this ____(interest)book I happened to read this book.中的不定式是做什么成分.