You will succeed in the end __________ you don't give up halfway.[ ]

A. even if

B. as long as

C. unless

D. as though

某一岩层是由粘土、淤泥等组成的泥质页岩，并含有莲的化石，说明当时的沉积环境是（）

A、湖泊和沼泽

B、热带浅海环境

C、炎热干旱环境

D、温湿茂密的森林