When it ______ research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.
| A．refers to | B．related to | C．comes to | D．talks to |
—We’ve spent too much time money recently
—Well,it isn’t surprising.Our friends and relatives ___around all the time
| A．are coming |
| B．had come |
| C．were coming |
| D．have been coming |
—Were you surprised by the ending of the film?
—No.I___the book,so I already knew the story
| A．was reading |
| B．had read |
| C．am reading |
| D．have read |
—Peter,where did you guys go for the summer vacation?
—We___busy with our work for months,so we went to the beach to relax ourselves
| A．were |
| B．have been |
| C．had been |
| D．will be |
—Why ,Jack,you look so tired！
—Well,I___the house and I must finish the work tomorrow
| A．was painting |
| B．will be painting |
| C．have painted |
| D．have been painting |
Excuse me.I___I was blocking your way
| A．didn’t realize |
| B．don’t realize |
| C．haven’t realized |
| D．wasn’t realizing |