such heavy pollution already, it may now be too late to clean up the river.
| A．Having suffered |
| B．Suffering |
| C．To suffer |
| D．Suffered |
_____ was very ______ that little Jim wrote the letter.
| A．It, careful | B．It, carefully |
| C．He, careful | D．He, carefully |
What is it _____ his daughter needs most？
| A．what | B．which | C．that | D．if |
Who was it _____ saved the drowning girl？
| A．since | B．as | C．that | D．he |
“How was ______ they discovered the entrance to the underground palace？” “Totally by chance.”
| A．it that | B．he that |
| C．it when | D．he which |
____ that caused him to serve dinner an hour later than usual.
| A．It was we being late | B．It was our being late |
| C．It was we were too late | D．It was because we were late |