零冠词短语arm in arm臂挽臂at first最初 at home在家中 at last最后，终于 at most至多 by hand手工catch fire着火 day after day 日复一日 day and night 日日夜夜day by day一天天地face to face面对面from beginning to end 自始至终from door to door挨家挨户 from east to west从东到西from time to time时不时地hand in hand手拉手in bed在睡觉 in danger处于危险中 lose heart灰心，丧气 lose weight减肥on foot步行 on time准时one by one一个接一个地step by step一步一步地take part in参加