16.Although _______ new energy sources will be developed, we must reduce our consumption of fossil fuels.
(A) there are likely
(B) there is the likelihood of
(C) it is likely that
(D) it is a likelihood that

There's a likelihood of + N   ;  The likelihood is that + 子句 

這題是選擇正確的片語來完成句子：

題目：
Although ______ new energy sources will be developed, we must reduce our consumption of fossil fuels.

選項如下：
(A) there are likely
(B) there is the likelihood of
(C) it is likely that
(D) it is a likelihood that

正確答案是：(C) it is likely that

解析：

這句話的主詞從屬子句為「new energy sources will be developed」，也就是一句完整的句子，所以我們需要能夠引導一個子句的表達方式。

各選項分析：

(A) there are likely
→ 錯誤。這個用法不完整，需要搭配形容詞或名詞作補語，例如 “There are likely problems” 或 “There are likely to be problems.”。

(B) there is the likelihood of
→ 錯誤。雖然語法正確，但這個結構後面要接名詞或動名詞（V-ing），不適合接完整子句。
例如：There is the likelihood of rain. 或 There is the likelihood of new energy sources being developed.（但原句是子句）

(C) it is likely that
→ 正確！這是標準的句型來引導一個完整的子句：
“It is likely that new energy sources will be developed.”

(D) it is a likelihood that
→ 錯誤。這不是常見或自然的用法。“Likelihood” 通常不用作主詞搭配 “it is.”

小補充：
   •   It is likely that + 子句 是最常見且自然的說法。
   •   There is a likelihood of + 名詞/V-ing 是另一個正確但語氣較正式的說法。
   •   The likelihood is that + 子句 也可以，但結構與選項不符。