答案：B分析：空格前为时间状语，后面是由that引导的从句，空格处缺少

答案：B分析：空格前为时间状语，后面是由that引导的从句，空格处缺少主句。只有(B)为完整的主谓结构，故选(B).参考译文：在十四世纪，人们发现涂有硝酸银的玻璃在炉中烧后会变黄

Kết quả (Anh) 1:

Answer: b analysis: spaces before time, followed by that before, spaces lack the main clause. Only (b) for the complete predicate structure, so choose (b). question: in the 14th century, it was discovered that silver nitrate-coated glass in a furnace to burn will turn yellow

Kết quả (Anh) 2:

Answer: B analysis: Before a space for the time adverbial, followed by a guided that clause, the lack of space at the main sentence. Only (B) for a complete subject-predicate structure, so choose (B) Passage: In the fourteenth century, it was discovered after will turn yellow glass coated with silver nitrate to burn in the furnace

Kết quả (Anh) 3:

Answer: B analysis: space for time, followed by a that clause, if lack of space. Only (b) to complete the subject predicate structure, so choose (b). Text: in the 14th century, it was discovered that coated with silver nitrate glass and burning in the furnace will turn yellow