From the ________ shown in the dead body, he ________to death by a certain poisonous chemical, but I can’t tell exactly which.

From the ________ shown in the dead body, he ________to death by a certain poisonous chemical, but I can’t tell exactly which.

1. A.
   symptoms; must have been poisoned
2. B.
   signs; should have been poisoned
3. C.
   symbols; could have been poisoned
4. D.
   appearances; may have been poisoned

From the ________ shown in the dead body, he ________to death by a certain poisonous chemical, but I can’t tell exactly which.

A. symptoms; must have been poisoned　　 B. signs; should have been poisoned

C. symbols; could have been poisoned　 D. appearances; may have been poisoned

From the ________ shown in the dead body, he ________to death by a certain poisonous chemical, but I can’t tell exactly which.

A. symptoms; must have been poisoned　　 B. signs; should have been poisoned

C. symbols; could have been poisoned　　 D. appearances; may have been poisoned