1. The patient was known... stool retention accompanied by nausea a month before his present
admission to the hospital.

а)to have
b)to have had
c)to be having

2. Sensitivity to this antibiotic was reported... not only in this animal but in the herd on the whole.

a)to be present
b)to have been present

3. Preventive vaccination was found...since no cases of hepatitis were diagnosed after its administration.

a)to be effective
b)to have been effective

4) Skin irritation was revealed...
after each parenteral administration of this medication.

a)to occur
b)to have occurred
c)to have been occurring​