Unit 2 – Gerunds and Infinitives
Unit 3 – Gerunds and Infinitives
Unit 6 – Gerunds and Infinitives
Unit 7 – Environmental Problems
Unit 7 – Gerunds and Infinitives
Unit 8 – Gerunds and Infinitives
Unit 9 – Gerunds and Infinitives
Unit 9 – Infinitives of Purpose
Unit 10 – Present Perfect Continuous
Unit 10 – Present Unreal Conditional/Second Conditional
Unit 10 – Real Conditional – Present
Unit 12 – For and Since and How Long Questions