The professor told me to start the research right now, ________ I was sure to fall behind.
This book ______ Tom’s father’s, because his name is on the book.
This question is ______ easy, all the students can answer the question.
I don’t know _________.
When we practice speaking English, we often end up _____ in Chinese.
----_____do you improve your listening? ----I improve it ______ listening to tapes. A. How; with B: What; with C: How; by D. What; by