3 sentences

1. 儿童必须至少4岁。

   ér​tóng bì​xū zhì​shǎo4 suì.

   Children must be at least 4 years old.

   Source: CCMatrix

2. 儿童必须至少七岁才能参加。

   ér​tóng bì​xū zhì​shǎo qī suì cái​néng cān​jiā.

   Children must be at least 7 years old to participate.

   Source: CCMatrix

3. 我们所有的客人必须至少年满18岁。

   wǒ​men suǒ​yǒu de kè​ren bì​xū zhì​shǎo nián​mǎn18 suì.

   All of our guests must be at least 18 years of age.

   Source: CCMatrix