Fourth-graders attend a class at Yangfangdian central primary school in Haidian District of Beijing, capital of China, June 8, 2020. Students in their fourth and fifth grades at primary schools in Beijing on Monday returned to school for the first time in this semester. (Xinhua/Ren Chao)

Students take the first class of the new term at Tonghui primary school in Shenyang, northeast China's Liaoning Province, June 8, 2020. Students in their third, fourth and fifth grades at primary schools in Shenyang returned to school on Monday. (Xinhua/Long Lei)

A student receives temperature check at Tonghui primary school in Shenyang, northeast China's Liaoning Province, June 8, 2020. Students in their third, fourth and fifth grades at primary schools in Shenyang returned to school on Monday. (Xinhua/Long Lei)

Students keep a safe distance from each other before entering the Tonghui primary school in Shenyang, northeast China's Liaoning Province, June 8, 2020. Students in their third, fourth and fifth grades at primary schools in Shenyang returned to school on Monday. (Xinhua/Long Lei)

Students learn how to correctly wash hands at Tonghui primary school in Shenyang, northeast China's Liaoning Province, June 8, 2020. Students in their third, fourth and fifth grades at primary schools in Shenyang returned to school on Monday. (Xinhua/Long Lei)

Students enter the campus of Tonghui primary school in Shenyang, northeast China's Liaoning Province, June 8, 2020. Students in their third, fourth and fifth grades at primary schools in Shenyang returned to school on Monday. (Xinhua/Long Lei)

Fourth-graders attend a class at Yangfangdian central primary school in Haidian District of Beijing, capital of China, June 8, 2020. Students in their fourth and fifth grades at primary schools in Beijing on Monday returned to school for the first time in this semester. (Xinhua/Ren Chao)

Fifth-graders attend a national flag raising ceremony at the classroom of Yangfangdian central primary school in Haidian District of Beijing, capital of China, June 8, 2020. Students in their fourth and fifth grades at primary schools in Beijing on Monday returned to school for the first time in this semester. (Xinhua/Ren Chao)

A fifth-grader (2nd R) receives the temperature check before entering the campus of Yangfangdian central primary school in Haidian District of Beijing, capital of China, June 8, 2020. Students in their fourth and fifth grades at primary schools in Beijing on Monday returned to school for the first time in this semester. (Xinhua/Ren Chao)

Fourth-graders attend a class at Yangfangdian central primary school in Haidian District of Beijing, capital of China, June 8, 2020. Students in their fourth and fifth grades at primary schools in Beijing on Monday returned to school for the first time in this semester. (Xinhua/Ren Chao)

Fifth-graders attend the national flag raising ceremony at the classroom of Yangfangdian central primary school in Haidian District of Beijing, capital of China, June 8, 2020. Students in their fourth and fifth grades at primary schools in Beijing on Monday returned to school for the first time in this semester. (Xinhua/Ren Chao)