B1 Grammar lessons cover the rules, patterns, and structures you need at the B1 Intermediate level. Each lesson explains a grammar point with clear examples, common mistakes to avoid, and practice opportunities. Topics are ordered to build on each other so you can work through them step by step.
Quick Answer The plural of symposium is symposia or symposiums. Both are correct. Symposiums is more common in everyday English. Symposia is used more in academic and formal writing. One: The symposium starts at nine o’clock.Many: The university held three symposiums this year. Symposium, Symposia, Symposiums — See the Pattern Look at these words. Can…
Quick Answer The plural of syllabus is syllabi or syllabuses. Both are correct. Syllabi is more common in schools and universities. Syllabus, Syllabi, Syllabuses — See the Pattern The word syllabus comes from Latin. That is why it has two plural forms. Look at these examples: Did you see the pattern? When there is one,…
Quick Answer The plural of stimulus is stimuli. It follows the Latin rule — words ending in -us change to -i for the plural. One: The bright light was a strong stimulus.Many: The scientists tested different stimuli. Stimulus, Stimuli — See the Pattern Look at these words. Can you see what happens? Did you see…
Quick Answer Software has no plural form. It is always software — never “softwares.” Example: “We installed new software on all the computers.” “Software” Never Changes — See Why Look at these sentences. What do you notice about the word software? Did you see? The word software stays exactly the same every time — whether…
Quick Answer The plural of species is species. The word never changes. One species, many species — always the same. One: This species is very rare. Many: These species are all endangered. One Species, Two Species — The Word Never Changes Look at these sentences. Can you see what happens? Did you see the pattern?…
Quick Answer The plural of radius is radii. You can also say radiuses — both are correct. Radii is more common. One: The radius of this circle is 5 cm.Many: The radii of these circles are all different. Radius, Radii, Radiuses — See the Pattern Look at these words. Can you see what happens? Did…
Quick Answer The plural of phenomenon is phenomena. One phenomenon, two phenomena. Do not add an S — “phenomenons” is not correct. Phenomenon and Phenomena — See the Pattern The word phenomenon comes from Greek. That is why the plural does not just add an S. Look at these examples: Did you see the pattern?…
Quick Answer The plural of octopus is octopuses. You might also hear octopi or octopodes, but octopuses is the most common and correct form. Example: “We saw three octopuses at the aquarium.” Octopus, Octopuses, Octopi — See the Options The word octopus comes from Greek. It means “eight feet.” Because it comes from Greek (not…
Quick Answer The plural of nucleus is nuclei. You might also see nucleuses, but nuclei is the form most people use, especially in science. Nucleus and Nuclei — See the Pattern The word nucleus comes from Latin. That is why the plural does not just add an S. Look at these examples: Did you see…
Quick Answer The plural of matrix is matrices. You can also say matrixes — both are correct. Matrices is more common. One: This matrix shows the data.Many: These matrices show the data. Matrix, Matrices, Matrixes — See the Pattern Look at these words. Can you see what happens? Did you see the pattern? These words…
