设N_A表示阿伏加德罗常数，下列说法正确的是（ ）           

A．标准状况下，22.4LCH₄和CH₂Cl₂的混合物所含有的分子数目为N_A

B．3g的甲基中含有的电子数为1.6N_A

C．0.5mol的有机物C₁₅H₃₂中含有的共键数为24N_A

D．现有乙烯、丙烯、丁烯的混合气体共14g，其原子数为3N_A

Everyone except Tom and John _______ there when the meeting began.

[      ]

A. is

B. was

C. are

D. were