［误］The little boy and girl walk along the street a hand in a hand.
［正］The little boy and girl walk along the street hand in hand.
［析］这是英语中的习惯用法，如：
bit by bit (逐渐)
day after (by) day (一天又一天)
day and night (日日夜夜)
face to face (面对面)
from A to Z (自始至终)
from time to time (再三)
hand in hand (手拉手)
shoulder by shoulder (肩并肩)