Past

• I cost
• you cost
• he/she/it cost
• we cost
• you cost
• they cost

Present

• I cost
• you cost
• he/she/it costs
• we cost
• you cost
• they cost

Future

• I will cost
• you will cost
• he/she/it will cost
• we will cost
• you will cost
• they will cost

Past

• I was costing
• you were costing
• he/she/it was costing
• we were costing
• you were costing
• they were costing

Present

• I am costing
• you are costing
• he/she/it is costing
• we are costing
• you are costing
• they are costing

Future

• I will be costing
• you will be costing
• he/she/it will be costing
• we will be costing
• you will be costing
• they will be costing

Past

• I had cost
• you had cost
• he/she/it had cost
• we had cost
• you had cost
• they had cost

Present

• I have cost
• you have cost
• he/she/it has cost
• we have cost
• you have cost
• they have cost

Future

• I will have cost
• you will have cost
• he/she/it will have cost
• we will have cost
• you will have cost
• they will have cost

Past

• I had been costing
• you had been costing
• he/she/it had been costing
• we had been costing
• you had been costing
• they had been costing

Present

• I have been costing
• you have been costing
• he/she/it has been costing
• we have been costing
• you have been costing
• they have been costing

Future

• I will have been costing
• you will have been costing
• he/she/it will have been costing
• we will have been costing
• you will have been costing
• they will have been costing