12.5 could, might:negative 1. One reason for this discrepancy is that the apparatus could / might not have been sensitive enough to detect minor constituents alternatively, the sample could / might have become contaminated with the air. 2. We would like to thank Professor Wallwork without whose help this study could / might not have been completed. 3. This could / might be explained by the fact that some severe cases could / might not have been diagnosed correctly because of alack of appropriate facilities in the hospital. 4. In each case, we found that x and y were identical in structure. This means that they could / might not have been discriminated in terms of this structure, but only in terms of their behavior. 5. These results clearly prove that the event could / might not have been a mere coincidence, but rather, that it must have been an integral part of the process. 6. Although some of the contributing factors could / might not have been detected by this pilot study, the results nevertheless show that 7. The same results could / might not have been obtained with the multispectral satellite data that is currently available, since they are not reliable enough. 8. Their support, without which this work could / might not have been done, is gratefully recognized. 9. This operation could / might not have been performed successfully on human beings without the preliminary years of work on animals. 10. Wei bcould / might not do all the tests within the allocated time, in fact we only managed to do three out of five. might, might 2. could 3. could, might 4. could 5. could 6. might (could) 7. could 8. could 9. could 10. could
