I see MONKEYS AT THE ZOO LAST WEKEND

1 I <SEE> MONKEYS AT THE ZOO LAST WEKEND   
2 WE <NOT /SEE > ANY CROCODILES AT THE ZOO YESTERDAY   
3 NAM <BUY> WATCH TV YESTERDAY 
4 MY SISTER  < NOT /DO> HER HOMEWORK LAST NIGHT