按年计费
Membership dues are billed annually and are available at several different participation levels.───会员费是以年度的形式来收取，并提供不同的参会形式。
biannually───adv.每半年地
millennially───千禧年
bilingually───双语
bimanually───双工
filled away───转帆向风；乘风前进
semiannually───adv.每半年
Hellenically───希腊化的