<span style="color:#000080;">1-For the cat to come in, the door was open.</span><br/><br/><span style="color:#ff0000;">2-The door was open for the cat to come in.</span><br/><span style="color:#800080;">3-The door was open for the cat to have come in.</span><br/><br/><span style="color:#0000ff;">4-The door must have been open for the cat to come in.</span><br/><span style="color:#800000;">5-The door must have been open for the cat to come in.</span><br/><br/>Which of the above sentences could mean:<br/><br/>The cat came in and therefore we can conclude that the door was open.<br/><br/>Gratefully.<br/>Navi.