rhythm method

method of contraception by avoiding sexual intercourse near the time of ovulation 安全期避孕法.

rheumatic, rheumatic fever, rheumaticky, rheumatics, rheumatism, rheumatoid, rheumatoid arthritis, rhinestone, rhino, rhinoceros, rhizome, rhododendron, rhomboid, rhombus, rhubarb, rhyme, rhymed, rhyming slang, rhythm, rhythm and blues, rhythmic, rhythmically, RI, rib, rib-cage, rib-tickling, ribald, ribaldry, ribbon, ribbon development, riboflavin, rice, rice-paper, rich, riches, richly, richness, Richter scale, rick, rickets,