What are the three killing mistakes in english grammar?

Confused between tenses. Lacked of confidence in speaking.

1.Wrong usage of tense.

2.Mistakes in subject verb agreement.

3.Inability  to understand proper meaning of phrase verbs and idioms

1.  One of the most common grammar mistakes happens around contractions, the combining of two words into one, such as "It’s vs. Its" or "They’re vs. Their vs. There."

2.  Use of "Less or fewer?"  I have less milk than my brother.  (Because you can’t count “milk”).  I have fewer glasses of milk than my brother. (Because you can count “glasses of milk”).

3.  Sally and me? Or Sally and I?  Confusion about when to use “me” and “I” is one of the most common grammar mistakes.

 

 

Its a future tense , past tense and conditional tense.Its very important to use correct sentence to describe the situation in easy and simplay way to understand ....xyz

1. Incorrect use of tenses.

2. Incorrect use of articles

3. Incorrect pronunciation.

Its Future Tense, Past Perfect Tense and Conditional Sentences.so I believe that if you fix the way you describe Future actions or Past Tense you’re English Grammar is going to be good.

   

Perfect vocabulary, Perfect sentence structures and Reading aloud everyday to train up speech organs.

the three killing mistakes  and unforgiveble ones are  the mis-use of tense  especially between simple and progressive .2:word_order mistakes ,ex:time normally goes after place but in Arabic it is the opposite.3:the mis_use of articles ex:the use of 'a' and 'the''.

1.Use of improper tense.2.Non-relavent pernountation.3.Spelling mistake.

Grammar mistakes can be found in all language items. From singular/plural nouns to tenses to prepositions to word order to parts of speech.  

In order to avoid such mistakes, teachers must tackle the core of the problem in language acquisition. To understand grammar fully, learners need to be exposed to a lot of language while reading/listening, notice specific items when they are used (i.e. in stories, in conversations), study the meaning/form/use of the item, make sure to work on drills, and engage in controlled and freer practice in different contextual environments.