If it is difficult to state definitely one or several ports, optional ports can be adopted.

假如难以明确写出一个或几个港口，就可以采用选择港这个办法。

youdao

If it is difficult to state definitely one or several ports, optional ports can be adopted.

假如难以明确写出一个或几个港口，就可以采用选择港这个办法。

youdao