to reach them on the phone, we sent an email instead

 A. Fail  B. Failed  C. To fail  D. Having failed

_________to reach them on the phone, we sent an email instead.

A. Fail            B. Failed             C. To fail          D. Having failed

_______to reach them on the phone, we sent an email instead.

A. Fail            B. Failed             C. To fail          D. Having failed

Prices reach equilibrium at the level at which quantity demanded ______ quantity supplied.

    A.is equal to       B.equal            C. equals to        D. is equal

_________ to reach them on the phone，we sent an email instead．

　　A．Fail　 　　　　　　　　　　B．Failed

　　C．To fail　　　　　　　　　　D．Having failed