Revision of the Passive Voice

Every year over 29,000 antelopes ________ (kill) in Tibet.

--- 一般现在时被动语态

2. In the past, the elephants __________ (kill) by farmers.

--- 一般过去时被动语态

are killed

were killed

3. In the past twenty years, a large number of bamboo areas ______________ (set up) to help pandas grow.

--- 现在完成时被动语态

have been set up