Question

---Have you heard of Earth Day?
--- Yes, We have only one Earth. We have no choice but ________ it.

A．protect

B．protected

C．protecting

D．to protect

Answer 1

D

试题分析: 句意：你听过地球日吗？听过，我们只有一个地球，我们除了保护它别无选择。Have后接带to不定式，故选D。