Answer:
1) estos 2) Does not make sense at all any one of them, I think it will make more sense if you put eaither Vosotros estais esperando a que comienze el curso, but my guess to that one is estas 3)same to the second one and to be hones it will make sense if you write Estos de aqui son mas chiquitos
Step-by-step explanation:
Sorry if I did not help a lot in this one, but to be honest the 2 and 3 did not make sense.