像arm in arm,hand in hand,face to face这样“器官+介词+器官（和前面的器官相同）”的

day by day 逐日
day after day 每日
one by one 逐个
bit by bit 一点点地
little by little 渐渐地
step by step 逐步地
by and by 逐渐
side by side 并排
face (nose) to face (nose) 面对面
back to back 背靠背
hand in hand 手拉手
arm in arm 挽手
mouth to mouth嘴对嘴
heart to heart 交心,谈心
neck and neck 并驾齐驱
eye to eye 赞同
head to head 交头接耳
shoulder to shoulder 并肩
on and on 继续
word for word 逐词地
out and out 十足的
inch by inch 一点一点地
like for like 以牙还牙
like attracts like 物以类聚
wheels within wheels 复杂的结构
diamond cut diamond 棋逢对手