Need to finish my TEFL crossword, can't figure out these clues;
1. When "to" appears before a verb, the verb is in what form? 10 letters.
2. Words can be classified into groups, also known as __? 6 letters
3. How would you describe this sentence: Mark told his students that they should study dilligently. It is called __ speech. 8 letters.
4. An 'anxious' grammar term!! 6 letters.