1£®We substituted a red ball ¡¡for¡¡ blue to see if the baby would notice.

2£®Were it not for science, we could not live a ¡¡comfortable¡¡ (comfort) life.

3£®It ¡¡is acknowledged¡¡ (acknowledge) that wealth doesn't necessarily mean happiness.

4£®I recommend him ¡¡to think¡¡ (think) very carefully before he does anything foolish.

5£®¡¡Occupying¡¡ (occupy) herself with routine office tasks, she had no time to attend to her children.

6£®Without sufficient ¡¡preparations¡¡ (prepare), you can hardly expect to answer all the questions correctly.

7£®Every time he interrupts me, he always makes ¡¡an¡¡ apology to me.

8£®It is required that the new employees ¡¡(should) be provided¡¡ (provide) safety training before they start to work.