单选题
This book will show the readers ______ can be used in other contexts. A. how that they have observed B. how what they have observed C. that how they have observed D. that they have observed
【正确答案】
B
【答案解析】[解析] how what they have observed can be used in other contexts如何将他们所观察到的应用于其他情况，what they have observed作宾语从句的主语，how引出宾语从句，其他三个答案不合句型。