This is an interesting small book which consists of six main parts. As the title and words on the cover said, this book helps you build your vocabulary, avoid pronunciation errors, sharpen your spelling, improve your grammar and express your ideas clearly and correctly if you can spend 15 minutes a day. I'm not sure but I believe it worth a try! Come read with me to prove it right or wrong! 

I read it on the subway this morning for the first part "Test Your English". Contents of Day 1 to Day 4 tests your pronunciation, vocabulary, spelling and grammar respectively.  I do have severe problems on vocabulary and grammar. Let's see one of the tests of it:

Test 5: Do You Have an Average Vocabulary?

If so, you will have no difficulty matching the two columns below. Seventy-five percent of the adults tested knew all these words.

          WORDS                                                             MEANINGS

1. imminent                                                        a. cleanse 

2. fluster                                                             b. flashy

3. rigid                                                                c. confuse

4. purge                                                              d. bring back to former excellence

5. rehabilitate                                                      e. hinder

6. latent                                                               f. pretend

7. gaudy                                                              g. stiff

8. feign                                                                h. coax

9. cajole                                                               i. hidden

10. impede                                                           j. likely to happen in the near future

How did you do?  I have to admit that I don't have a good vocabulary.

The Spelling Test really confused me a lot. I doubted my answers nearly EVERY TIME! In modern times, we can check our spellings with the help of smart phones and computers. So I guess if we don't train ourselves, we may too much depend on these tools.

liquefy or liquify?

Only five verbs end in -efy rather than the common -ify; liquefy, putrefy, rarefy, stupefy, and of course, defy.

wrench

V-T If you wrench something that is fixed in a particular position, you pull or twist it violently, in order to move or remove it. 猛拽; 猛扭

例句：He felt two men wrench the suitcase from his hand. 

V-T If you wrench yourself free from someone who is holding you, you get away from them by suddenly twisting the part of your body that is being held. 挣脱

例句：She wrenched herself from his grasp.

No one's grammar is perfect, of course, but conspicuously poor English wrench the listener's attention away from what a speaker is saying and direct it to the error he is making.

wrench 有扳手的意思，在这里作者用它动词的意思很形象地表现了糟糕的演讲者会让他的听众从他的演讲内容中挣脱出来直接去关注他的错误。