Question

【题目】We must keep a positive attitude toward the future______we may encounter some difficulties.

A．however B．as if

C．even if D．since

Answer 1

【答案】C

【解析】选C。句意：即使我们有可能遇到一些困难，我们也必须对未来保持乐观的态度。even if即使，引导让步状语从句。however后应接形容词/副词；as if好像；since自从。