We laugh at jokes, but seldom __________ about how they work.

A．we think          B．think we          C．we do think        D．do we think

We laugh at jokes, but seldom ____________ about how they work.

A．we think             B．think we                 C．we do think             D．do we think

We laugh at jokes，but seldom　　　　 about how they work．

A．we think　　 B．think we 　 C．we do think　　　 D．do we think

We laugh at jokes，but seldom____________about how they work．

   A．we think         B．think we       C．we do think        D．do we think

We laugh at jokes，but seldom ????????? about how they work．

A．we think???????? B．think we?????? C．we do think??????? D．do we think

We laugh at jokes，but seldom____________about how they work．

   A．we think         B．think we       C．we do think        D．do we think

 We laugh at jokes，but seldom            about how they work．

   A．we think         B．think we      

C．we do think        D．do we think

We laugh at jokes，but seldom　　　　　 about how they work．_{w_w*w.k_s*5_u.c_o m}

　 A．we think　　　 B．think we　　　

C．we do think　 　　D．do we think