1.Our……culture…………. traditions should be maintained and introduced to friends all over the world. ( vì là chủ từ).

2. We should cut down the use of …………fertilize…………… and pesticides for cultivation. (we số nhiều)

3.We need to think how to use them………effectively………… (vì là trạng từ đứng sau túc từ thì thêm ly)

4.Tropical rainforests have helped to keep the environment in balance but recent ..........forests............. means more pollution and serious natural disasters. (forest thêm s, recent: gần đây là số nhiều)

5.It is advised that .........tour............must be responsible for their action during the trip. (S + modal verb + be + V3 )

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