contact by friction

例句：

1. 1. They need to maintain good contact with their clients.
   他们需要与客户保持良好的联系。
2. 2. The two countries have been in contact for several years now.
   这两个国家已经保持了几年的联系。
3. 3. The scientist contacted the team before they arrived.
   科学家在团队到达之前与他们取得了联系。