A.每半個(gè)月補(bǔ)充一次電 B.20天補(bǔ)充一次電 C.每個(gè)月補(bǔ)充一次電 D.每?jī)蓚€(gè)月補(bǔ)充一次電
A.5 B.10 C.15 D.20
A.1 B.2 C.3 D.4