单选题 Only after he has acquired considerable facility in speaking ______ to learn to read and to write.
A. he began B. will he begin
C. did he begin D. must he begin

【正确答案】 B
【答案解析】[解析] only置于句首，句子要部分例装。因从句中动词为现在完成时，所以得出正确答案B。