Iftheoperation________carefullyprepared,itwouldnothavebeensuccessful.
A、wasnotC
语法题：虚拟语气。
Aftermonthsofvoyage,Columbusarrivedin______laterprovedtobeanewcontinent.
Studentsshould_____theirowninterestsaswellasdotheirschoolwork.
Itisimportantto________yourskinfromtheharmfulstrongsunlight.
Theypreferto_______therestofthemorningwalkinginthegarden.
Hewas______towithdrawfromrunningforthepresidency.
