_____ man first made use of electricity is not exactly known yet.
A: Since
B: Although
C: Whether
D: When
A: Since
B: Although
C: Whether
D: When
举一反三
- ______ the sports meeting of this year will be held is not known yet. A: If B: Whether C: What D: That
- ______ the 2012 Olympic Games will be held in London is not known yet. A: Whether B: If C: Whenever D: That
- ()youcan’tanswerthisquestion,wehavetoasksomeoneelseforhelp. A: Although B: While C: Whether D: Since
- His first question was_____Tom had arrived yet. A: if B: that C: whether D: what
- People decided to honor Edison when ______. A: he made his electric light B: the first invention was made C: he died more than 70 years ago D: the country realized the importance of electricity