( )6.The stones they carried were used houses and bridges.
A.to build B.for building C.to be built D.Both A and B
( )7.He here since breakfast.
A.must come B.must have been C.have come D.must be
( )8.At that time I noticed him past.
A.walk B.to walk C.walked D.walking
( )9.I all the exercises before our teacher collected them.
A.have finished B.finished C.had finished D.finish
