wE lEArn From thE pAssAgE thAt ______.
A．thE BACtEriA ArE only EFFECtivE AgAinst thrEE spECiEs oF BEEtlEs
B．FiElDs' tEChniquE is lEss EFFECtivE in wintEr
C．FiElDs' tEChniquE mAy kill nEArly All thE BEEtlEs At -10℃
D．insECts mAy DEvElop rEsistAnCE AgAinst thE BACtEriA