like: I saw them this morning. They were waiting at the bus stop. → →
720
I saw them this morning. They were waiting at the bus stop. ☊ 
Tôi đã gặp họ sáng nay. Họ đang đợi ở bến xe bus. ☊ I saw them this morning. They were waiting at the bus stop. ☊ Tôi đã gặp họ sáng nay. Họ đang đợi ở bến xe bus. ☊