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We must keep our room clean. Dirt and disease go        , you know.

A. from time to time                 B. hand in hand

C. step by step                       D. one after another

We must keep our room clean. Dirt and disease go _____ you know.

A. from time to time                 B. hand in hand

C. step by step                      D. one after another

We must keep our room clean. Dirt and disease go _____, you know.

A. from time to time                 B. hand in hand

C. step by step                      D. one after another

We must keep our room clean. Dirt and disease go ____________, you know.

A. from time to time                 B. hand in hand

C. step by step                      D. one after another

We must keep our room clean. Dirt and disease go _____, you know.

  A. from time to time   B. hand in hand   C. step by step   D. one after another