Children play at a reopened amusement park on a street in Burlingame city in north California, the United States, on March 29, 2021. Most businesses in San Mateo county where Burlingame sits have been reopened with limited client visits as the county advanced to a less restrictive orange tier (the second lowest) on the state's Blueprint for a Safer Economy. (Photo: Xinhua)

(Photo: Xinhua)

A child plays at a reopened amusement park on a street in Burlingame city in north California, the United States, on March 29, 2021. Most businesses in San Mateo county where Burlingame sits have been reopened with limited client visits as the county advanced to a less restrictive orange tier (the second lowest) on the state's Blueprint for a Safer Economy. (Photo: Xinhua)

(Photo: Xinhua)