heteachertoldthemsincelight________(travel)fasterthansound,lightning________(appear)togobeforethunder.

Thosewho’dliketovisittheexhibition________(sign)yournameshere.

Somemoleculesarelargeenough________(see)undertheelectronicmicroscope.

Wooddoesnotconductelectricity;________.

Wewerebusy________(get)thingsreadyforthetrialproductionwhenhephonedus.