Here are the correct forms of each word in brackets:

### Exercise 26:
1. Sylvie is **considering** options. (consider)
2. One momentary lapse in **concentration** could prove fatal. (concentrate)
3. Sylvie got into an **argument** with the teacher. (argue)
4. You'll just have to be **patient** and wait till I'm finished. (patience)
5. We had a **discussion** with them about the differences between Britain and the US. (discuss)
6. I **explained** that an ambulance would be coming soon. (explain)
7. You will be **instructed** where to go as soon as the plane is ready. (instruct)
8. This is an image which persists in the popular **imagination**. (imagine)
9. The picture was at a **slight** angle. (slight)
10. A **conversationalist** is a person who is good at talking to others, especially in an informal way. (conversate)

### Exercise 27:
1. It's **surprising** how many people applied for the job. (surprise)
2. The feel of it, all cold and slimy, **disgusted** him. (disgust)
3. It was a **stressful** time for all of us. (stress)
4. It must be **worrisome** for you not to know where he is. (worry)
5. Sylvie stamped her foot in **annoyance**. (annoy)
6. Her behaviour really made me **angry**. (anger)
7. Sylvie was **embarrassed** at her own behaviour. (embarrass)
8. She showed complete **fear** in the face of danger. (fear)
9. You'll jump from your seat with **excitement**. (excite)
10. I’m feeling more **relaxed** about the future now. (relax)