16. Baths use twice as much water as showers. However, I suggest taking a shower. (B. however)
17. I'd love to play volleyball, but I have to complete an assignment. (C. but)
18. Lan failed her English, so she has to do the test again. (C. because)
19. Minh got wet because he forgot his raincoat. (B. because)
20. We should buy a ladder because we need to fix the roof. There must be a strong wind blowing. (D. so)