Someone is following us.
Someone is following us.
Explanation
Present Continuous Tense
Active Voice: Subject + is/am/are + First of verb + ing + object.
Passive Voice: Object + is being/am being/ are being + third form of verb + by + subject.
Present Continuous Tense
Active Voice: Subject + is/am/are + First of verb + ing + object.
Passive Voice: Object + is being/am being/ are being + third form of verb + by + subject.