______(3)
A.while
B.if
C.when
D.so

______(4)
A.which
B.what
C.how
D.when

______(6)
A.origin
B.cause
C.source
D.reason

______(8)
A.why
B.where
C.when
D.whereas

________(14)
A.heat
B.heated
C.heating
D.hot

_________(2)
A.clock
B.catch
C.discover
D.went

_________(4)
A.because
B.when
C.late
D.discover

_________(5)
A.when
B.missed
C.ran
D.catch

_________(7)
A.because
B.ran
C.clock
D.late

_________(9)
A.catch
B.ran
C.went
D.late