Choose the correct forms
1. l lost/have lost my smartphone just now.
2. she finished/has finished her homework already.
3. last year Sarah travelled/has travelled to the UK.
4. she started/has started a new job at the office.
5. why has/was he gone/went to Australia?
6. she mailed/has mailed me twice this week.

1. The correct form is "I lost my smartphone just now."
Explanation: The word "just now" indicates that the action of losing the smartphone happened in the past, so the simple past tense "lost" should be used.

2. The correct form is "She has finished her homework already."
Explanation: The word "already" suggests that the homework was completed before the present moment, so the present perfect tense "has finished" should be used.

3. The correct form is "Last year Sarah traveled to the UK."
Explanation: The phrase "last year" indicates a specific time in the past, so the simple past tense "traveled" should be used.

4. The correct form is "She has started a new job at the office."
Explanation: The word "has started" implies that the action of starting a new job happened before the present moment, so the present perfect tense should be used.

5. The correct form is "Why has he gone to Australia?"
Explanation: The use of "has" in the question suggests that the action of going to Australia happened before the present moment, so the present perfect tense should be used.

6. The correct form is "She has mailed me twice this week."
Explanation: The present perfect tense "has mailed" is used to indicate that the action of mailing happened before the present moment but within the time frame of "this week."