B.) when
C.) since
D.) although
[单选题]A. unlessB. sinceC. lestD. although
[单选题][A] Although[B] Unless[C] As[D] If
[单选题][A] Unless [B] As [C] Lest [D] Although
[单选题]A.) BecauseB.) AsC.) SinceD.) Although
[单选题]A.) butB.) becauseC.) unlessD.) when
[单选题]___________[A] Since [B] If [C] Unless [D] While
[单选题]A. providedB. sinceC. althoughD. supposing
[单选题]___________A.] when[B] since[C] for[D] whereas
[单选题][A] While [B] When [C] Though [D] Unless
[单选题]A.) thoughB.) ifC.) asD.) unless