[单选题][A] who [B] when [C] where [D] which
[单选题][A] While [B] When [C] Though [D] Unless
[单选题]A. when B once C while D whereas
[单选题]___________[A] when[B] once[C] while[D] whereas
[单选题][A] so [B] once [C] as [D] where
[单选题][A] which[B] where[C] here[D] there
[单选题][A] but [B] whereas [C] though [D] while
[单选题][A] as [B] when [C] if [D] so
[单选题]___________A.] when[B] since[C] for[D] whereas
[单选题][A] what [B] which [C] why [D] how