________ the problem, he wouldn't have committed those mistakes.
| A．If he understood | B．Had he understood |
| C．When he had understood | D．If he would understood |
Twentymiles_________alongwaytocover.
| A．were | B．are | C．is | D．seemtobe |
Tenthousanddollars_________alargesumofmoney.
| A．are | B．is | C．were | D．seem |
Veryfew_________hisaddressinthetown.
| A．knows | B．know | C．areknowing | D．hasknown |
Notonlytheworkersbutalsothemachine____notthere.
| A．are | B．were | C．is | D．has |
Iknowthatall ________gettingonwellwithher.
| A．was | B．is | C．are | D．were |